I have a 305HO, That when it was built, they used 308/350 truck heads. Not only are the chambers 78cc'c, but the valves are very small. I don't want to use the stock-light casting heads and the "World" heads are a little spendy for me. Seeing that the 283 has the same bore, could I use maybe the 283 power-pack heads? I believe the 283 had flat top pistons. I think the 283 heads are 58-60cc's. I would like to find a head with 64cc's which would give me 9.7 compression. 58cc's would give me 10.58 compression and I would like to be able to run this on pumped gas.