I have a 305HO, that was built with the wrong heads. "World" heads are a little spendy for me. The 283 has the same bore as the 305, soooo, could I use 283 heads on a 305? I would like to find heads with 64cc as that would give me 9.7 compression. I think that the 283 fuelie & Power Pack also had flat top pistons as my 305HO. I don't want to use the stock 305 heads because of cracking problems.