[pholmann09]

pre 71' the hp and torque numbers that pontiac put out were very modest the 365 hp 400 were actually over 400 hp but they lowered the numbers for insurance purposes the post 71' motors were actually the same with a crappy head on the they all had flat top pistons they just opened the combustion chamber to lower the compression due to the clean air act of 1970( that was the first step of many that has destroyed muscle cars) I have a 67' gto with the 365 hp 400 and I cant run my 670 heads because it wont run on anything less that 100 octane low lead airplane fuel, I could run a mix of 110 and 93 but you are talking alot of money to just start it up and pull it out of the garage!