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Old 11-10-2007, 07:46 PM
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compression question

I'm sorry if this question may sound extremely like a newbie, but here goes how much compression can you gain on head gaskets alone? I have 10:1 and would like to get closer to 11:1. Can't I mill the head to a smaller combustion chamber and also gain some compression ratio. Again extemely new to this. Thanks for the response.

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Old 11-10-2007, 08:03 PM
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well the simple answer to your question is: yes.

give us more details about what you've got and we can probably provide a better response:

1) what heads are you running
2) What block are you running
3) any modifications done to either?
4) what is the thickness of your current head gasket?
5) what pistons are you running
6) what camshaft and rockers are you running (want to make sure your valves won't hit the pistons)
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Old 11-10-2007, 08:57 PM
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Typically you gain 3% or less HP with one point of compression. So if you have 200 hp now, you'll have 206 after the compression change. Not enough to get me excited, especially with the cost of gasoline it will take to run it. Compression should be matched to your cam. A mild cam with high compression makes high cranking pressures and detonation is a real problem. More cam, more compression makes sense, but more compression for more power doesn't. Its tons of labor, money, and octane requirement for 3% HP.
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Old 11-10-2007, 08:57 PM
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some info is not known due to the fact this is a crate engine,what i do know
edelbrock performer heads 170cc runners 64 chambers unmolested
matching cam 234/244 at.050 488/510 lift
KB silvolite 10:1 hyper pistons with valve reliefs
gen 1 sbc i believe machined for 0 deck
guessing on head gaskets but assuming standard thickness
Im trying to pump this engine combo past the 500 hp without a retro fit roller cam. 11:1 compression would help me with afr 195, 1.6 rockers, and a victor jr intake. Thanks for help
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Old 11-11-2007, 11:37 AM
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Originally Posted by F-BIRD'88
If the motor is O decked you cannot use a thin head gasket. the piston to head clearance would be too small. The piston will smack the head at high rpm.
You need .035" to .040" clearance including the gasket.
Change the camshaft. That cam will not make 500hp even with AFR heads+Vic JR +11:1.

A solid lifter cam is preferred on a 350ci motor that you expect to make 500hp as the rpm will be quite high. Use a Comp cams 294S magnum at minimum.
A Isky #201547 would work very well too.
In fact if you were to fully port your RPM heads (molest them to flow 260cfm), shave them a bit (59cc) for a 11:1 finished cr, (O deck clearance) swap to a port matched vic JR+750-850cfm carb with the above Isky cam and 1-3/4" headers, you would make 500+hp.

I found more paper work and the block was aligned honed and machined to .010 in the hole. Also this is a 383 and if I was to change the cam I was
going with extreme energy 244/244 at .050 with .536 lift. What do you think? Do you believe the edelbrock heads with 170 cc runners even ported can be 500+ heads?I noticed your sign in picture and its odd you responded I bought the camaro 1 hour north of detroit I believe in Sariana or something like that in your backyard it took 13 hours one way. thanks for the reply
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