question about cometic head gaskets and compression?

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Sep 17, 2007 | 08:09 PM

quiet_storm98

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question about cometic head gaskets and compression?

I am looking into getting some .040 cometic head gaskets but i noticed they said they are for a 3.910 bore but they will still work fine for a stock bore ls1 right? Also what kind of scr and dcr would i have with these and a set of tea 5.3 heads that have been milled .015? I have tried the search but i cant find the cr calculator. thanks for your help guys.

Sep 17, 2007 | 09:32 PM

3.4camaro

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they will work fine for 3.910 bore. I have them on my stock bore h/c setup.

Sep 17, 2007 | 10:00 PM

Thimble

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Yes, they're perfect for stock bore. You can go bigger on gasket hole than bore size, just not smaller.

SCR for a ~60cc chamber on a LS1 would be in the 11.4/11.5 ballpark, assuming no piston notching.

My TEA 5.3 heads were milled .020" to achieve 59cc and with .040" Cometics and some piston flycutting I'm at 11.5.

Can't comment on DCR without knowing what cam you're running.

Sep 18, 2007 | 10:00 PM

quiet_storm98

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Quote:

Originally Posted by Thimble

o ok thanks i will be running a 231/233 .612/.598 111+2 cam..i figure that i will have to flycut so im guessing my cr will be a lil lower then yours

Sep 19, 2007 | 03:37 AM

BOWTIE

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Quote:

Originally Posted by quiet_storm98

o ok thanks i will be running a 231/233 .612/.598 111+2 cam..i figure that i will have to flycut so im guessing my cr will be a lil lower then yours

Not sure what TEA does with those heads, but they just might be OK without flycutting. Check for sure, but you just might be able to make it. I know PRC supposedly sinks the valves just a tad to help with p/v clearance on their larger profiles, but there 2.5 5.3's will supposedly clear their V2/V3 camshafts with an .040 gasket and they supposedly mill their heads .005-.010 as well.

Sep 19, 2007 | 06:39 AM

brad8266

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Quote:

Originally Posted by quiet_storm98

I have tried the search but i cant find the cr calculator. thanks for your help guys.

4th down on the search list, "calculator"

Compression Calculator

Sep 19, 2007 | 08:40 PM

quiet_storm98

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Quote:

Originally Posted by brad8266

4th down on the search list, "calculator"

Compression Calculator

thanks alot...thats exactly what i was looking for...well anyway using that it calculated my scr at 11.64:1 and dcr at 8.76:1 without flycutting. Isn't that a lil high?? that was calculating that my heads are milled to 60cc, they really may be 61cc or so.