CR problem

Okay, I'm curious. I'm no Pontiac expert but build Chevy engines and am up for the compression expression. Are you aiming for a stock-type engine build or are you shooting for performance with available components? I ask because you state the common street performance desire to "run on pump gas" but I'm unfamiliar with the "RA IV cam". What's the cam data, vehicle weight, gearing and application (towing, mileage, racing or mid-life crisis hot rod:) Really interested in what the compression ratio is with your current configuration too. There's a lot that goes into avoiding preignition & detonation, which sounds like your basic concern. But, the simple static compression increase that comes with reduced head volume might not be a problem at all if the dynamic compression if affected appropriately by altered valve timing and combustion chamber shape. But, there are definitely things that you can do to help, like cylinder-to-head clearance. Drink

"birds4ever" wrote in message news:1161176671 snipped-for-privacy@sp6iad.superfeed.net...

He says the cam specs are as follows. " The RA IV cam is .516 lift with 230/240 duration (GM #9794041). It was run in the Ram Air IV motors during the '68 thru '71 heyday." Yeah. All things being equal, I Think, raising the compression with smaller heads is preferable to domed pistons. The domes inhibit the flame front (= lost power to a certain extent). It may even help with detonation through better quench (But, now I'm just thinking out loud). It does make sense to not have a piston crown up there to pimp-slap the head, though:) A race engine makes tradeoffs that we don't need to approach which is where domes might be the right choice. Now that we have the cam, need to do the math to find out the static compression. LET's GET IT OONN!!! Drink P.S. I'm jealous. Wish I still had my '69...

"69SScamaro" wrote in message news:U4B_g.152$%T3.128@trndny03...

Looks reasonable and it agrees with our gut feeling, as expected. I'd definitely agree with the recommendation for smaller heads. Pump gas shouldn't be a problem in that neighborhood. Depending how close you want to get to a magic compression ratio, you can do some extra math (there are free downloadable calculators or I can volunteer via e-mail) and consider some tweaks to your plan, i.e. shave the heads, various gasket thicknesses, block decking, etc. Mornin', Drink

Do they have a calculator that figures all that out for you ? If so give me a link I would like to try it. We always did it the old fashioned way using calculus, algebra and normal math... the only part is the metric conversion. (ci to cc) if you do have a calc to do that how close were we to what it came up with ?