I am rebuilding a 1975 350 engine and I have 2 sets of heads to choose from. I am putting in 9.3:1 comp. forged pistons. The block is bored .030. The pistons are rated 9.3:1 at .030 with 64 cc heads. I have 76cc heads off another 350 (77-79 casting # on the block is 14013679 I dont know what this is out of as there is no vin # in the ussual spot and the internet has been useless up to here. It is a 4 bolt main. If you know about this # can you help me here too?) and I have 64 cc heads off a 1980 305. Both have 1.94 intake valves and 1.5 in exhaust valves. What set should I use on this engine. This will be going in my 1979 camaro and I want all the power i can get out of the engine. All my head figures are off a web site and may be inaccuarate. I will post the head #'s as soon as i can read them off the heads. I know the valves are the same size on both heads as Ive compared the two. I have been told to use the 350 heads and I cant figure out why.I figure that if the ratio is 9.3 with 64cc heads it will be lower with 76 and id like at least 9:1 comp. If any other info is needed ask, I will be more than willing to find out. I would really appreciate some help on this as it seems im the only one in favor of the smaller chamber heads.