owned this car for 20 years, and still don't know a lot about pontiac drive train. Had lots of chevy ,(68 ss, 63 corvette,23 t with 350 LT1) .Need to catch up on pontiacs. I"m looking for a 428, because of the 4 bolt mains, better nickle content in block (being built before 1970). 455 might be better,But they seem to be a lot of money, plus I would like a big block that can take the revs a little, one of the reason the 403 gotta go. I do admit, I don't no much about pontiacs "so be gentle".

ps: not interested in doing anything more to the 403 engine want a pontiac engine