[nova66mussl]

I am freshening up my son's 350 engine for his 71 Camaro. It is basically stock with 3973487 75cc heads and factory rated at 8.5 to 1 compression. I have a set of 8060 Vortec heads which have 64 cc chambers. How much would these heads raise the compression ratio?

 

[bowtie0069]

If it has 8.57-1 now (just threw some numbers in program) the change would get you to 9.55. That's using a gasket .041" compressed; if you used GM 10105117 .028" gaskets you'd get about 9.8-1.

 

[nova66mussl]

Thanks for the info. So still very friendly to pump gas. I didn't want to jack it up and that be an issue. This will have a mild cam also. Just trying to warm it up a little on a mild budget. I have Performer intake, rockers, valve covers etc. that came off my Nova a couple of years ago so this will be a good use for them. Thanks again for your help bowtie69.

 

[MarkW]

Give some thought about some steel shim head gaskets like these....http://www.summitracing.com/parts/FPP-1094/ Worth another .3-.4 points of compression.

 

[nova66mussl]

One more question regarding the vortec heads...do they require a different pushrod length than that of a stock 350?

 

[Dan_Lebherz]

I used the steel shim gaskets with the Vortec Heads for about 10.1-10.2 Cr, if I remember correctly. I had no problem with detonation running 93 octane pump gas. I never tried regular or mid grade.