I have 1970 bbc block with 119 cc pro topline 320 aluminum heads, stock TRW pistons 11.54 compression . I will use auto trans ,4.11 12 bolt . The motor is going it to a 1970 chevelle hard top. MY question is can I run this motor on the street on 91 pump gas? If not is there a camshaft that will make it so I can run the motor on 91 pump gas?:waving:

YEP! Aluminum heads conduct heat so it's like running a 10:54 motor. Now as far as making a 1/4 mile pass I'd step up to race gas, and yes cam profile plays a BIG role on cylinder pressure.

Unless you're running more timing, why run race gas? It burns slower and makes less power.

what pistons do you have??

So the pistons are rated at 11.5:1? You should measure everything because unless the short block and heads are setup by a good shop you will find tolerances everywhere. If the block is not decked I wouldn't be surprised to find your 11.5:1 rated to be less than 11:1 in reality. You'll also find different compression ratio on different cylinders due to the left & right deck height being different.

Too much quench may cause detonation too, I think I may have had an issue with that even though I was at 10.5-1 with .049 quench :(

What is your quench distance and what cam is in it now?