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Re: The '49-'62 V8... anything out there?

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  • jvandecreek25
    ... Engine tests ... Seller wants ... good buy ... That s not a bad price if it is complete, if you have to spend extra to replace missing accessories, like
    Message 1 of 25 , Dec 9, 2004
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      > Jerry Brown (an old guy)
      >
      > PS...I'm looking at a 76 Cad 500 engine for my 36 Chev coupe.
      Engine tests
      > out at 123-128 psi on all cyl. so I'm thinking its pretty good.
      Seller wants
      > $375. I'm new to the cad engine market so don't know if this is a
      good buy
      > or not. Any advice?

      That's not a bad price if it is complete, if you have to spend
      extra to replace missing accessories, like manifolds, brackets and
      pulleys, the price could easily double, so try to find as complete a
      package as you can, Does it include the trans? most DeVills (RWD)
      will come with the trans, but Eldos usually don't.
    • Jerry Brown
      PS...I m looking at a 76 Cad 500 engine for my 36 Chev coupe. Engine tests ... Seller wants ... good buy ... That s not a bad price if it is complete, if you
      Message 2 of 25 , Dec 9, 2004
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        PS...I'm looking at a 76 Cad 500 engine for my 36 Chev coupe.
        Engine tests
        > out at 123-128 psi on all cyl. so I'm thinking its pretty good.
        Seller wants
        > $375. I'm new to the cad engine market so don't know if this is a
        good buy
        > or not. Any advice?

        That's not a bad price if it is complete, if you have to spend
        extra to replace missing accessories, like manifolds, brackets and
        pulleys, the price could easily double, so try to find as complete a
        package as you can, Does it include the trans? most DeVills (RWD)
        will come with the trans, but Eldos usually don't.


        Its complete right down to A/C compressor, alternator, belts, carb,
        manifolds and some wiring. No transmission but that is no problem as I have
        a recently rebuilt TH400 from a 74 472 engine that is a basket case. I
        assume the bell housing is the same whether DeVille or Eldorado. Am I
        correct?

        I looked up the HP and Torque for this engine and have to say its less than
        impressive for the displacement. I can see why so many go to higher
        compression, performance cam, headers and different intake.

        Nother question: Is it acceptable practice to mill the heads to raise
        compression a point to a point-and-a-half? If so do you have to go to
        different length pushrods or will there still be sufficient clearance
        between valves and piston? I'm looking for about 9.5:1 CR to help out
        performance. I know the best way to go is usually different pistons but I'm
        trying to keep the costs reasonable.

        Thanks. You guys have been great with the information and advice.

        Jerry Brown
      • jvandecreek25
        ... a ... as I have ... case. I ... Am I ... less than ... raise ... to ... clearance ... out ... pistons but I m ... Don t worry too much about the seemingly
        Message 3 of 25 , Dec 9, 2004
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          --- In Cadillac_Performance_Association@yahoogroups.com, "Jerry
          Brown" <jerome@p...> wrote:
          > PS...I'm looking at a 76 Cad 500 engine for my 36 Chev coupe.
          > Engine tests
          > > out at 123-128 psi on all cyl. so I'm thinking its pretty good.
          > Seller wants
          > > $375. I'm new to the cad engine market so don't know if this is a
          > good buy
          > > or not. Any advice?
          >
          > That's not a bad price if it is complete, if you have to spend
          > extra to replace missing accessories, like manifolds, brackets and
          > pulleys, the price could easily double, so try to find as complete
          a
          > package as you can, Does it include the trans? most DeVills (RWD)
          > will come with the trans, but Eldos usually don't.
          >
          >
          > Its complete right down to A/C compressor, alternator, belts, carb,
          > manifolds and some wiring. No transmission but that is no problem
          as I have
          > a recently rebuilt TH400 from a 74 472 engine that is a basket
          case. I
          > assume the bell housing is the same whether DeVille or Eldorado.
          Am I
          > correct?
          >
          > I looked up the HP and Torque for this engine and have to say its
          less than
          > impressive for the displacement. I can see why so many go to higher
          > compression, performance cam, headers and different intake.
          >
          > Nother question: Is it acceptable practice to mill the heads to
          raise
          > compression a point to a point-and-a-half? If so do you have to go
          to
          > different length pushrods or will there still be sufficient
          clearance
          > between valves and piston? I'm looking for about 9.5:1 CR to help
          out
          > performance. I know the best way to go is usually different
          pistons but I'm
          > trying to keep the costs reasonable.
          >
          > Thanks. You guys have been great with the information and advice.
          >
          > Jerry Brown
          Don't worry too much about the seemingly low hp. ratings, in actual
          performance in a light vehicle there is not of much noticable
          difference, you could mill the heads but a better choice is to swap
          on a set of 425 heads, compression will be about 10:5 and will give
          you and easy 40 hp more, not the best breathing for all out racing,
          but fine up to around 4500 rpm, making for strong street performance
          cheap, next best change is a good cam, then an Edelbrock intake.
          Your 472 Trans will bolt right up.
        • Jerry Brown
          Thanks for the additional information re. 425 heads on 500 engine. Are the differences in the combustion chamber so that I don t need to change out valve train
          Message 4 of 25 , Dec 9, 2004
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            Thanks for the additional information re. 425 heads on 500 engine. Are the
            differences in the combustion chamber so that I don't need to change out
            valve train etc.?

            Don't worry too much about the seemingly low hp. ratings, in actual
            performance in a light vehicle there is not of much noticable
            difference, you could mill the heads but a better choice is to swap
            on a set of 425 heads, compression will be about 10:5 and will give
            you and easy 40 hp more, not the best breathing for all out racing,
            but fine up to around 4500 rpm, making for strong street performance
            cheap,
          • jvandecreek25
            ... Are the ... change out ... The late 500 heads have 120cc chambers, while the 425 heads have 96cc chambers, this is where the increase in compression comes
            Message 5 of 25 , Dec 9, 2004
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              --- In Cadillac_Performance_Association@yahoogroups.com, "Jerry
              Brown" <jerome@p...> wrote:
              > Thanks for the additional information re. 425 heads on 500 engine.
              Are the
              > differences in the combustion chamber so that I don't need to
              change out
              > valve train etc.?

              The late 500 heads have 120cc chambers, while the 425 heads have
              96cc chambers, this is where the increase in compression comes from.
              The 425 head has the same valve sizes, and the same intake and
              exhaust ports as the late 500 head, the factory did remove some
              weight by opening up the area where the push-rods pass through, but
              this change has no effect on performance or durability.
              Earlier '69-'73 heads do have better, more direct exhaust ports and
              work better on a race type engine, but the compression goes to over
              12:1 when used with the flat top pistons of a '74-'76 500(and 472)
              and these stock cast pistons are prone to disintegrating at those
              compression ratios, this combination is not at all streetable on
              available pump gas.
              So for "Bang for the buck",
              Install the 425 heads, use a 425 head gasket(can be an old used
              one) to locate the positions of the extra steam holes that will need
              to be drilled in the block deck of the 500, a 3/8" electric drill
              with the appropriate size bit is all that will be required, assemble
              the heads to the block using 500 head gaskets. no other
              modifications or non stock parts are needed.
            • david brode
              Jerry, The 74- 76 500s have 120+ cc chambers and a very small dish. If the bores look good, you could just deck the block for a .040 or so assembled quench,
              Message 6 of 25 , Dec 11, 2004
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                Jerry,

                The '74-'76 500s have 120+ cc chambers and a very small dish. If the
                bores look good, you could just deck the block for a .040" or so
                assembled quench, and whack the heads to get to *maybe* 9.5-1. Fyi -
                KB makes no dish flat tops for it if it needs bored [which I doubt it
                will].

                Another option would be dished KB designed for the early heads. They
                give 10-2-1 or so with the '68-'73 heads [76cc]. Another option is to
                use 107cc 425 heads on your shortblock. They'll put you a little over
                9.5-1. The 425 heads don't flow as well as yours, but a little work
                and they'll do ok. The 76cc heads flow better than yours, btw, but
                not much in stock form. More fyi - 2.11"/1.66&1.77" pontiac valves
                fit the 107 and 120cc heads perfectly. For larger valves on the 76cc,
                aftermarket valves are available from the caddy
                parts vendors.
                Dave




                > Nother question: Is it acceptable practice to mill the heads to
                raise
                > compression a point to a point-and-a-half? If so do you have to go
                to
                > different length pushrods or will there still be sufficient
                clearance
                > between valves and piston? I'm looking for about 9.5:1 CR to help
                out
                > performance. I know the best way to go is usually different pistons
                but I'm
                > trying to keep the costs reasonable.
                >
                > Thanks. You guys have been great with the information and advice.
                >
                > Jerry Brown
              • david brode
                jvandecreek25, The 425 heads will not gain near that much in compression. It has been said that they are 96cc, but I believe they are more like 107cc or so.
                Message 7 of 25 , Dec 11, 2004
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                  jvandecreek25,

                  The 425 heads will not gain near that much in compression. It has
                  been said that they are 96cc, but I believe they are more like 107cc
                  or so. That figure comes from experts that I trust.

                  CR on a stock engine can vary. Assuming a stock late 500 is 8-1, and
                  the heads are 120cc, the 13cc reduction in combustion space would
                  raise the CR to 8.7-1. Assuming the stock engine was 8.5-1, the
                  change would give 9.25-1.

                  It would take a change in combustion space of apx 27.5cc to raise
                  compression of an 8.5-1 engine to 10.5-1.
                  Dave




                  much about the seemingly low hp. ratings, in actual
                  > performance in a light vehicle there is not of much noticable
                  > difference, you could mill the heads but a better choice is to swap
                  > on a set of 425 heads, compression will be about 10:5 and will give
                  > you and easy 40 hp more, not the best breathing for all out racing,
                  > but fine up to around 4500 rpm, making for strong street
                  performance
                  > cheap, next best change is a good cam, then an Edelbrock intake.
                  > Your 472 Trans will bolt right up.
                • jvandecreek25
                  ... 107cc ... and ... After I posted I realised I had over-shot on the amount of compression increase, the figure I gave was one I had seen posted
                  Message 8 of 25 , Dec 12, 2004
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                    --- In Cadillac_Performance_Association@yahoogroups.com, "david
                    brode" <dbrode@h...> wrote:
                    >
                    > jvandecreek25,
                    >
                    > The 425 heads will not gain near that much in compression. It has
                    > been said that they are 96cc, but I believe they are more like
                    107cc
                    > or so. That figure comes from experts that I trust.
                    >
                    > CR on a stock engine can vary. Assuming a stock late 500 is 8-1,
                    and
                    > the heads are 120cc, the 13cc reduction in combustion space would
                    > raise the CR to 8.7-1. Assuming the stock engine was 8.5-1, the
                    > change would give 9.25-1.
                    >
                    > It would take a change in combustion space of apx 27.5cc to raise
                    > compression of an 8.5-1 engine to 10.5-1.
                    > Dave

                    After I posted I realised I had over-shot on the amount of
                    compression increase, the figure I gave was one I had seen posted
                    elsewhere,and I never took time to confirm it.
                    However the figure for the 40 hp increase did come directly from Al
                    Betker of MTS,one of the most experienced Cadillac builders to be
                    found.
                    If this 40 hp improvement comes from an increase to only 9.25-1,
                    then so much the better.
                  • jvandecreek25
                    ... the ... Fyi - ... it ... They ... to ... over ... work ... 76cc, ... I m looking for about 9.5:1 CR to help out performance. I know the best way to go is
                    Message 9 of 25 , Dec 12, 2004
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                      --- In Cadillac_Performance_Association@yahoogroups.com, "david
                      brode" <dbrode@h...> wrote:
                      >
                      > Jerry,
                      >
                      > The '74-'76 500s have 120+ cc chambers and a very small dish. If
                      the
                      > bores look good, you could just deck the block for a .040" or so
                      > assembled quench, and whack the heads to get to *maybe* 9.5-1.
                      Fyi -
                      > KB makes no dish flat tops for it if it needs bored [which I doubt
                      it
                      > will].
                      >
                      > Another option would be dished KB designed for the early heads.
                      They
                      > give 10-2-1 or so with the '68-'73 heads [76cc]. Another option is
                      to
                      > use 107cc 425 heads on your shortblock. They'll put you a little
                      over
                      > 9.5-1. The 425 heads don't flow as well as yours, but a little
                      work
                      > and they'll do ok. The 76cc heads flow better than yours, btw, but
                      > not much in stock form. More fyi - 2.11"/1.66&1.77" pontiac valves
                      > fit the 107 and 120cc heads perfectly. For larger valves on the
                      76cc,
                      > aftermarket valves are available from the caddy
                      > parts vendors.
                      > Dave


                      I'm looking for about 9.5:1 CR to help out performance. I know the
                      best way to go is usually different pistons but I'm trying to keep
                      the costs reasonable.
                      Jerry Brown


                      Jerry wanted to keep the costs reasonable, to "deck the block "
                      will require a complete disassembly, and is hardly a way to keep the
                      cost down, and as he stated he did not want to get into piston
                      changes.
                      I made my recommendation based on the premise that he wanted an
                      inexpensive power increase for a engine that was going into a street
                      rod, no it is not the 'ultimate' performance build up, but if it is
                      not being used as a race car, there is no need to pursue a lot of
                      expensive modifications that are unnecessary for strong street
                      performance. Jessie
                    • Jerry Brown
                      Actually I was speculating about just milling the 500 heads to get the increased compression ratio. Since the engine would be out of the car its no big deal to
                      Message 10 of 25 , Dec 12, 2004
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                        Actually I was speculating about just milling the 500 heads to get the
                        increased compression ratio. Since the engine would be out of the car its no
                        big deal to pull the heads and have a valve job done and to mill them for
                        increased compression...So long as you don't booger up the valve train
                        ratios. It seems to me that if you mill the heads, say .040, that it would
                        drop the head lower with respect to the valve train i.e., closer to the
                        center of the camshaft, and might result in any of a number of unintended
                        results.
                        In order to keep everything in the same ratio you would have to account for
                        being .040 closer. Seems to me that pushrods that are .040 shorter should
                        compensate or taking .040 off the top of the valve stem might as long as the
                        keepers would still fit. Doesn't seem right that you wouldn't have to do
                        anything but mill to do the job right. Likewise decking the block would have
                        the same result of moving the head closer to the center of the cam. I guess
                        the right question is can milling or decking be done without unintended
                        catastrophic consequences and if so how should one compensate for the
                        changes.

                        Jerry Brown


                        -----Original Message-----
                        From: jvandecreek25 [mailto:jvandecreek@...]
                        Sent: Sunday, December 12, 2004 1:15 PM
                        To: Cadillac_Performance_Association@yahoogroups.com
                        Subject: [Cadillac_Performance_Association] Re: The '49-'62 V8...
                        anything out there?




                        --- In Cadillac_Performance_Association@yahoogroups.com, "david
                        brode" <dbrode@h...> wrote:
                        >
                        > Jerry,
                        >
                        > The '74-'76 500s have 120+ cc chambers and a very small dish. If
                        the
                        > bores look good, you could just deck the block for a .040" or so
                        > assembled quench, and whack the heads to get to *maybe* 9.5-1.
                        Fyi -
                        > KB makes no dish flat tops for it if it needs bored [which I doubt
                        it
                        > will].
                        >
                        > Another option would be dished KB designed for the early heads.
                        They
                        > give 10-2-1 or so with the '68-'73 heads [76cc]. Another option is
                        to
                        > use 107cc 425 heads on your shortblock. They'll put you a little
                        over
                        > 9.5-1. The 425 heads don't flow as well as yours, but a little
                        work
                        > and they'll do ok. The 76cc heads flow better than yours, btw, but
                        > not much in stock form. More fyi - 2.11"/1.66&1.77" pontiac valves
                        > fit the 107 and 120cc heads perfectly. For larger valves on the
                        76cc,
                        > aftermarket valves are available from the caddy
                        > parts vendors.
                        > Dave


                        I'm looking for about 9.5:1 CR to help out performance. I know the
                        best way to go is usually different pistons but I'm trying to keep
                        the costs reasonable.
                        Jerry Brown


                        Jerry wanted to keep the costs reasonable, to "deck the block "
                        will require a complete disassembly, and is hardly a way to keep the
                        cost down, and as he stated he did not want to get into piston
                        changes.
                        I made my recommendation based on the premise that he wanted an
                        inexpensive power increase for a engine that was going into a street
                        rod, no it is not the 'ultimate' performance build up, but if it is
                        not being used as a race car, there is no need to pursue a lot of
                        expensive modifications that are unnecessary for strong street
                        performance. Jessie








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                      • david brode
                        jvandecreek25, [bottom post] ... Al ... I have never CC d a pair myself. Al claims they re 96cc, iirc. Other experts claim 107cc. Dave
                        Message 11 of 25 , Dec 12, 2004
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                          jvandecreek25,

                          [bottom post]

                          <dbrode@h...> wrote:
                          > >
                          > > jvandecreek25,
                          > >
                          > > The 425 heads will not gain near that much in compression. It has
                          > > been said that they are 96cc, but I believe they are more like
                          > 107cc or so. That figure comes from experts that I trust.
                          > >
                          > > CR on a stock engine can vary. Assuming a stock late 500 is 8-1,
                          > and
                          > > the heads are 120cc, the 13cc reduction in combustion space would
                          > > raise the CR to 8.7-1. Assuming the stock engine was 8.5-1, the
                          > > change would give 9.25-1.
                          > >
                          > > It would take a change in combustion space of apx 27.5cc to raise
                          > > compression of an 8.5-1 engine to 10.5-1.
                          > > Dave
                          >
                          > After I posted I realised I had over-shot on the amount of
                          > compression increase, the figure I gave was one I had seen posted
                          > elsewhere,and I never took time to confirm it.
                          > However the figure for the 40 hp increase did come directly from
                          Al
                          > Betker of MTS,one of the most experienced Cadillac builders to be
                          > found.
                          > If this 40 hp improvement comes from an increase to only 9.25-1,
                          > then so much the better.

                          I have never CC'd a pair myself. Al claims they're 96cc, iirc. Other
                          experts claim 107cc.
                          Dave
                        • david brode
                          Jessie, [bottom]
                          Message 12 of 25 , Dec 12, 2004
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                            Jessie,

                            [bottom]


                            <snip

                            > Jerry wanted to keep the costs reasonable, to "deck the block "
                            > will require a complete disassembly, and is hardly a way to keep
                            the
                            > cost down, and as he stated he did not want to get into piston
                            > changes.
                            > I made my recommendation based on the premise that he wanted an
                            > inexpensive power increase for a engine that was going into a
                            street
                            > rod, no it is not the 'ultimate' performance build up, but if it is
                            > not being used as a race car, there is no need to pursue a lot of
                            > expensive modifications that are unnecessary for strong street
                            > performance. Jessie

                            Well, the reason I suggested decking the block for a tight quench and
                            whacking the heads a bit, was because he said that money was an
                            issue. Decking the block 20-30 thou costs just $65-$80 around here.
                            Cutting the heads .050" or so would be a few more bucks, but not too
                            much. Of course, once it's apart, hot tanmk, cam bearings, etc would
                            cost him some. Personally, I would want to ring and bearing it
                            anyway.

                            The 425 head swap might be a much better bang per buck, I admit. As I
                            see it, for a '74-'76 500, other than the 425 heads, the only other
                            affordable option is to change to the dished KBs and 76cc heads to
                            get any decent compression increase. Even the true flat top KBs on
                            the 120cc heads aren't going to gain much over the very small dish
                            stock late pistons.
                            Dave
                          • Preston III
                            I ve never decked the block, or shaved the heads of a Caddy engine, but if it s anything like a Chevrolet small block, there s a limit that you can go before
                            Message 13 of 25 , Dec 12, 2004
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                              I've never decked the block, or shaved the heads of a Caddy
                              engine, but if it's anything like a Chevrolet small block,
                              there's a limit that you can go before you have to do some
                              machining to the intake manifold too. I expect that if you
                              go past a certain extent, then you'll be in for spending
                              even a few dollars more!

                              Don't forget to inquire as to whether the changing geometry,
                              and clearances of the intake/head surfaces may require a
                              specific gasket, such as something extra thick.

                              Also, in a true performance application, you may consider
                              port matching the intake manifold to the intake side of
                              the cylinder heads, as this is the dimension that will change
                              as you go shaving things.


                              Preston III


                              --- david brode <dbrode@...> wrote:

                              >
                              > Jessie,
                              >
                              > [bottom]
                              >
                              >
                              > <snip
                              >
                              > > Jerry wanted to keep the costs reasonable, to "deck the block "
                              > > will require a complete disassembly, and is hardly a way to keep
                              > the
                              > > cost down, and as he stated he did not want to get into piston
                              > > changes.
                              > > I made my recommendation based on the premise that he wanted an
                              > > inexpensive power increase for a engine that was going into a
                              > street
                              > > rod, no it is not the 'ultimate' performance build up, but if it is
                              > > not being used as a race car, there is no need to pursue a lot of
                              > > expensive modifications that are unnecessary for strong street
                              > > performance. Jessie
                              >
                              > Well, the reason I suggested decking the block for a tight quench and
                              > whacking the heads a bit, was because he said that money was an
                              > issue. Decking the block 20-30 thou costs just $65-$80 around here.
                              > Cutting the heads .050" or so would be a few more bucks, but not too
                              > much. Of course, once it's apart, hot tanmk, cam bearings, etc would
                              > cost him some. Personally, I would want to ring and bearing it
                              > anyway.
                              >
                              > The 425 head swap might be a much better bang per buck, I admit. As I
                              > see it, for a '74-'76 500, other than the 425 heads, the only other
                              > affordable option is to change to the dished KBs and 76cc heads to
                              > get any decent compression increase. Even the true flat top KBs on
                              > the 120cc heads aren't going to gain much over the very small dish
                              > stock late pistons.
                              > Dave
                              >
                              >
                              >
                              >
                              >




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                            • david brode
                              Jerry, I ve only seen a few late 500s apart, but they all were pretty decent as far as deck to piston. Assuming you have eom pistons and they re good shape,
                              Message 14 of 25 , Dec 12, 2004
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                                Jerry,

                                I've only seen a few late 500s apart, but they all were pretty decent
                                as far as deck to piston. Assuming you have eom pistons and they're
                                good shape, and a 40-50 thou gasket is used, a .020" to *maybe .025"
                                deck cut will give you a nice tight assembled quench. El-cheapo cast
                                replacement pistons are often 20+ thou shorter than oem. I would
                                shoot for 040" assembled quench, regardless. Experts use either
                                Felpro of Corteco gaskets. The Coretcos are a little better, but
                                thicker, btw. .044"-.048" installed, iirc. You may need to stick the
                                piston out of the hole a bit wioth those. The 472/500 heads can be
                                cut way down. 050" is nothing on those, afaik. The 425 heads' deck
                                isn't as thick, and experts say not to cut them much over 040".

                                As far as rocker geometry, you can use shorter pushrods. You can also
                                have a good stock cam re-ground, and that'll reduce the base circle a
                                bit. Maybe enough to make up for the head/block cut. Most of the
                                caddy parts vendors offer re-ground cams, btw, but most grinders will
                                do one for you if you have a decent stock core. A note on that; most
                                grinders want to use profiles with 10+ extra exhaust duration. Afaik,
                                it's not needed on a caddy, esp with the 76cc heads. Even the 120cc
                                heads' stock exhaust port flows well enough to allow same duration on
                                intake and exh. Some experts even say that when ported, the caddy
                                heads flow so well on exhaust side that they use a little less
                                exhaust duration!

                                As far as higher lift cams, you may need to snip a little from the
                                top of the guides for clearance there. The '68 up seals are a joke.
                                You can use the normal old umbrella valve seals from the '67 429
                                caddys. SBchevy springs can be used, but you'll need to get creative
                                with shimming. The caddy springs are very tall. The new behive
                                springs offered for fords and LS1 chevs work better, with a retainer
                                change, as they fit the caddy spring pad, and are taller than std sbc
                                springs. If you have a freindly machine shop, they'll probably have
                                some larger diameter used retainers from something that'll fit the
                                behive springs. Just make sure they fit with the 11/32" valve
                                keepers. Unlike the sbc or behive springs, larger o.d. springs will
                                require pricey spring seats and more machine work. If you don't have
                                a machine shop that you can trust, you might want to buy a spring
                                package from one of the vendors. If you use stock rockers, choose a
                                cam grind with nice slow ramps, as quick ramps are hard on the stock
                                stuff. When cam shopping, make sure to tell them that you want slooow
                                ramps. Fast ramps are hard on the stock T pedistals and rockers.
                                Dave

                                Brown" <jerome@p...> wrote:
                                > Actually I was speculating about just milling the 500 heads to get
                                the
                                > increased compression ratio. Since the engine would be out of the
                                car its no
                                > big deal to pull the heads and have a valve job done and to mill
                                them for
                                > increased compression...So long as you don't booger up the valve
                                train
                                > ratios. It seems to me that if you mill the heads, say .040, that
                                it would
                                > drop the head lower with respect to the valve train i.e., closer to
                                the
                                > center of the camshaft, and might result in any of a number of
                                unintended
                                > results.
                                > In order to keep everything in the same ratio you would have to
                                account for
                                > being .040 closer. Seems to me that pushrods that are .040 shorter
                                should
                                > compensate or taking .040 off the top of the valve stem might as
                                long as the
                                > keepers would still fit. Doesn't seem right that you wouldn't have
                                to do
                                > anything but mill to do the job right. Likewise decking the block
                                would have
                                > the same result of moving the head closer to the center of the cam.
                                I guess
                                > the right question is can milling or decking be done without
                                unintended
                                > catastrophic consequences and if so how should one compensate for
                                the
                                > changes.
                                >
                                > Jerry Brown
                                >
                                >
                                > -----Original Message-----
                                > From: jvandecreek25 [mailto:jvandecreek@c...]
                                > Sent: Sunday, December 12, 2004 1:15 PM
                                > To: Cadillac_Performance_Association@yahoogroups.com
                                > Subject: [Cadillac_Performance_Association] Re: The '49-'62 V8...
                                > anything out there?
                                >
                                >
                                >
                                >
                                > --- In Cadillac_Performance_Association@yahoogroups.com, "david
                                > brode" <dbrode@h...> wrote:
                                > >
                                > > Jerry,
                                > >
                                > > The '74-'76 500s have 120+ cc chambers and a very small dish. If
                                > the
                                > > bores look good, you could just deck the block for a .040" or so
                                > > assembled quench, and whack the heads to get to *maybe* 9.5-1.
                                > Fyi -
                                > > KB makes no dish flat tops for it if it needs bored [which I doubt
                                > it
                                > > will].
                                > >
                                > > Another option would be dished KB designed for the early heads.
                                > They
                                > > give 10-2-1 or so with the '68-'73 heads [76cc]. Another option is
                                > to
                                > > use 107cc 425 heads on your shortblock. They'll put you a little
                                > over
                                > > 9.5-1. The 425 heads don't flow as well as yours, but a little
                                > work
                                > > and they'll do ok. The 76cc heads flow better than yours, btw, but
                                > > not much in stock form. More fyi - 2.11"/1.66&1.77" pontiac valves
                                > > fit the 107 and 120cc heads perfectly. For larger valves on the
                                > 76cc,
                                > > aftermarket valves are available from the caddy
                                > > parts vendors.
                                > > Dave
                                >
                                >
                                > I'm looking for about 9.5:1 CR to help out performance. I know the
                                > best way to go is usually different pistons but I'm trying to keep
                                > the costs reasonable.
                                > Jerry Brown
                                >
                                >
                                > Jerry wanted to keep the costs reasonable, to "deck the block "
                                > will require a complete disassembly, and is hardly a way to keep the
                                > cost down, and as he stated he did not want to get into piston
                                > changes.
                                > I made my recommendation based on the premise that he wanted an
                                > inexpensive power increase for a engine that was going into a street
                                > rod, no it is not the 'ultimate' performance build up, but if it is
                                > not being used as a race car, there is no need to pursue a lot of
                                > expensive modifications that are unnecessary for strong street
                                > performance. Jessie
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                > Yahoo! Groups Links
                              • david brode
                                Preston, Good point. I ve decked a couple of them, but only 10-20. There was no need to cut the intake, or intake side of head. The intake may ride up on the
                                Message 15 of 25 , Dec 12, 2004
                                • 0 Attachment
                                  Preston,

                                  Good point. I've decked a couple of them, but only 10-20. There was
                                  no need to cut the intake, or intake side of head. The intake may
                                  ride up on the heads a wee bit, but unless a large amount of mat'l
                                  was cut, the ports can be re-aligned when port matching.

                                  If it was a problem, the intake could be cut, or the intake side of
                                  the head, although the valve cover bolt hole bosses there make it a
                                  bit tricky.

                                  I know that this issue is common, as the .015" shorter 6.735" forged
                                  olds rods are often used in the caddy. Another old combo is 7" olds
                                  rods and 403" olds pistons. That combo is 40-50 thou short, so I'm
                                  sure it's been addressed.
                                  Dave


                                  III <prestoniii2002@y...> wrote:
                                  > I've never decked the block, or shaved the heads of a Caddy
                                  > engine, but if it's anything like a Chevrolet small block,
                                  > there's a limit that you can go before you have to do some
                                  > machining to the intake manifold too. I expect that if you
                                  > go past a certain extent, then you'll be in for spending
                                  > even a few dollars more!
                                  >
                                  > Don't forget to inquire as to whether the changing geometry,
                                  > and clearances of the intake/head surfaces may require a
                                  > specific gasket, such as something extra thick.
                                  >
                                  > Also, in a true performance application, you may consider
                                  > port matching the intake manifold to the intake side of
                                  > the cylinder heads, as this is the dimension that will change
                                  > as you go shaving things.
                                  >
                                  >
                                  > Preston III
                                  <snipped
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