Hi i have a set of 243 heads that sit at 60cc, i need to find out what kind of cc forged piston i can go with that will get me to 11.1 compression but no higher or even 10.98 if so. The package im goin to purchase have -12 dish, any idea what it will be with a -12 or do i need to get a diffrent cc. I would appreciate some info from people who really know there stuff. thanks
Matt

4.0 crank
6.125 rod
stock ls1 bore, just going to clean the block up not going to take any out.
milled 60 cc heads


Or if anybody can give me there specs to go with considering i have a set of 60 cc heads, but i have a stock block, and im going to order a 383 kit just dont know what sizes with accommodate these heads your help is greatley appreciated

 

I am not an expert, but -12 cc seems a bit big (if you are N/A which I assumed for you CR of 11.1). I would say you would be looking somewhere in the range of -2 to -3cc at the most, but like I said I am not an expert. I am sure other more experience members will pitch in with some good info, good luck with your build.

 

you need to list a lot more info! bore and stroke being among the top of the list. -12cc on a 3.898 is an entirely different compression than -12cc on a 4.125 bore!

 

What are your cam specs?

 

Comp cam 230/236 .601 .612 114 lsa

 

he already did that, he listed

"4.0 crank
6.125 rod
stock ls1 bore, just going to clean the block up not going to take any out.
milled 60 cc heads"

which would be 4 inch stroke, 6.125 rods, stock bore. correct me if I am wrong

 

Do you know the compression height of the pistons in the kit? Piston to deck height affects the calculation and in absence of this measurement I used a '0' deck height. I also assumed a .040" thick head gasket.

Here's the calculation with 60cc combustion chambers:




Here's what it takes to get to 10.98:1 SCR:



Provide some additional data and I'll recalculate.

 

What is your lobe center angle or how much advance is ground into the cam? I assumed it has 4 degrees of advance for my calculations and think you'll be fine with the 12cc pistons. I would try to get the pistons about .006-.008 out of the hole to optimize quench and compression(this may require decking the block).