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RE: [Cadillac_Performance_Association] Re: The '49-'62 V8... anything out there?

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  • 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 1 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 2 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 3 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 4 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 5 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 6 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 7 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 8 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 9 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








                      Yahoo! Groups Links
                    • 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 10 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 11 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 12 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 13 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 14 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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