I'm trying to get all my parts together to put my new engine in this Memorial day weekend and TSP sent me the wrong head gaskets.

I originally was going with .045" cometics to obtain a 8.54 DCR, 11.38 SCR, and .038 Quench.
They sent me .040" instead which puts me at 8.65 DCR, 11.53 SCR, and .033 Quench.

Am I going to have problems running this on 91 octane?


Also, does anyone know off hand if Patriots LS6 heads are exactly 64cc?

 

I know patriot does a "clean up" mill so I doubt they are *exactly* the same combustion chamber size as stock if it's a 243 casting ur talking about.

 

Yeah the 243 version. So you think it would be less.
I emailed Gunnar but he hasn't been on for a while.

 

ttt for the morning crew.

 

It takes .007" milling to remove 1cc from an LS1 head. I forget what PP does for a clean up mill, but TSP does .003. So if using .003, it'll be about half of one cc.

https://ls1tech.com/forums/showpost....2&postcount=41

 

Yeah I thought I remembered that too. So if that's correct, the heads should be right at 64cc and my numbers above should be pretty accurate.


I've been reading a lots of posts about what people are running for DCR & SCR on pump gas and seen a few running higher than me without problems, but I wonder if the added weight of a fullsize truck is going to offset that a bit.

I hate to get it all together to find out that it knocks on premium.

 

If it does, add a gallon or two of pain thinner. Its only about $6 a gallon from the store, and it will raise your octane rating by a few. when you think about it, its not much more expensive than gas is right now, and itll let you run a heap more compression. The tight quench is helping you too.

 

Yeah but this is going to be my DD, so I really don't want to mess around with adding extra stuff to the gas every week.

If I'm not mistaken, a tighter quench helps with resisting against detonation correct?

 

Yes, the tighter quench does help. Its not that big of a pain in the *** to buy a few cans at a time and dump one in right before you fill up the tank. People may look at you a little funny though .

 

Personally since it's a DD, I would wait on the correct stuff. I don't think it's worth it to risk detonation problems since you obviously planned on different, and more stable, numbers.

 

Zick, PP heads I had on my vette last year were 64.2-64.4 cc's. I know this because I cc'd them. I changed to a set of AFR 205's this year milled .024 to 62 cc's with .040 Cometics and have zero issues with knock. Remember that less quench will help. Car produced 404/385 with a small cam.

 

Thanks man, I'm really just considering trying these out and see what happens. I guess the worst thing is that I'll have to pull the heads and switch gaskets.
Wish me luck fellas, I think I'm gonna see what happens.