Loading ...
Sorry, an error occurred while loading the content.

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

Expand Messages
  • 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 1 of 25 , Dec 12, 2004
    • 0 Attachment
      --- 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 2 of 25 , Dec 12, 2004
      • 0 Attachment
        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 3 of 25 , Dec 12, 2004
        • 0 Attachment
          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 4 of 25 , Dec 12, 2004
          • 0 Attachment
            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 5 of 25 , Dec 12, 2004
            • 0 Attachment
              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
              >
              >
              >
              >
              >




              __________________________________
              Do you Yahoo!?
              Yahoo! Mail - Find what you need with new enhanced search.
              http://info.mail.yahoo.com/mail_250
            • 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 6 of 25 , Dec 12, 2004
              • 0 Attachment
                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 7 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
                Your message has been successfully submitted and would be delivered to recipients shortly.