Pontiacs are even MORE limited than Mopars, as far as cubic inches, because of bore space.

Chief's motor was done by Butler as stated, has a cast block and Edelbrock heads worked over by Butler. The motor is more or less a twin to the motor in Butler's own Pro-Mod Tempest, which is the quickest true Pontiac powered car in the country.

Chief is supposedly building a better motor with some billet parts, but not to make it bigger, but to make it stronger, so the wick can be turned up...........ie more boost. Stuff on cast motors tend to move around when you hit them with loads of boost. At cash days, they were worried about burning the crank out of the motor because of oiling problems, associated with the block either being cracked, or moving around under boost. He can make more boost with the turbos he has, if the motor could take it