im not sure of this relating to pontiac transmissions but you can swap a chevy 400 trans into a 350 case and shed 20+ punds of aluminum doing it. the case does take the beating with no problems! that said you might check into doing the same with your pontiac transmission. also many here have converted to the 200r4 transmission but as stated in afore mentioned posts... IT AINT CHEAP! cost is around 2000$ for a fairly good transmission that will handle the power your plan on putting to it! id stick with the 350 or convert to manual if your worried about the fun factor!