i call cometic and they state i can go 120 thick to reduce the compression anyone think this is a bad idea? i was thinking of gettin the .98 thickness. below are my options
A = .027" to .051" (.69mm to 1.3mm) Thick
B = .056" to .075" (1.42mm to 1.91mm) Thick
C = .080" to .098" (2.03mm to 2.5mm) Thick
D = .120" to .140" (3.05mm to 3.56mm) Thick

One of my blocks has been 0.070" over for 12 years with no problems.

Yes that is a bad idea. You will probably be more prone to detonation with that large of a quench. I went 0.051" before but that was the limit. As Dennis stated earlier you want the smallest quench possible. If you have new pistons on the way I would send them back for different ones or different heads.
My $0.02

11.5:1 is race gas only territory.

No money for different heads but you have money to replace/fix the motor when it breaks ?

Don't take my post too harshly but here it goes anyway :
You are trying to talk yourself into, and have others agree, that somehow you will be okay. I'm here to firmly stand on two feet and say you won't be okay.

BTW: Reducing timing / crazy thick headgaskets / wrong cam / etc,etc to try to save a motor from too high compression running lower fuel quality than it should is not a fix...not even a crutch.

BTW#2: I dispise the word 'crutch.' Motors and 'crutches' never get a long.

Build a motor for how you are going to use it. All components should closely match each other. This is the cheapest and most fun combo.

Your welcome. From a Voice of reason. LOL.

i am not trying to have other agree . I am not fimiliar with a bbc checy so thats why I have all the questions. Now I am trying to save as much as possible without replacing parts that are good. If you would have read the begining post I purchased this BROKEN!!! I AM JUST TRYING TO PICK UP THE PIECES AND AVOID HAVING IT BREAK ON ME LIKE IT DID ON THE GUY THAT WAS GUIDED THE WRoNG DIRECTION.. if i am better of with different heads so be it. I would hate to buy new one but it is what it is!....

If i were you and you could fix this motor for cheap and get it running right on race gas then i would sell it to a street guy and go buy a stock marine engine :) Probably be best/easiest all around

checked everything and they gave me the wrong information along the lines had the wrong rotating assembly part from the old owner... I went and got all the parts on the broken short block and determines that infact my compression will be 9.7:1 so I assume all this was for nothing but thanks for everyone that chimed in! Now gotta check out what cam will work best in this.

L92 HEADS 100CC
Mahle forged 4032 -3.0cc flat top
4.2500" stroke lightweight 4340 steel
6.385" standard H-Beam

Call RMbuilder, (585) 654-8583 no need to call anyone else

I second that, RM Builder designed my 427 BBC in my 242. absolutely excellent motor. In addition Bob is a fantastic guy to work with!

Call bob.... designed my valvetrain for my 428 sbc...love it