Power gluid to a 4 speed

I want to change my 2 speed power gluid to a 4 speed
Do I have to have a pontiac bell houseing? or will a chevy bell houseing bolt up to a pontiac engine?
Will any GM 4 speed trans bolt up to the bell houseing.

O I'm working on a 1968 firebird 350
Another idea I've had is going to a TH 350 trans
will any GM TH350 bolt up to the pontiac engine
or does it have to be for a pontiac?
I know I have to watch the end shaft lenth.
Thanks John

I want to change my 2 speed power gluid to a 4 speed
Do I have to have a pontiac bell houseing? or will a chevy bell houseing bolt up to a pontiac engine?
Will any GM 4 speed trans bolt up to the bell houseing.

O I'm working on a 1968 firebird 350
Another idea I've had is going to a TH 350 trans
will any GM TH350 bolt up to the pontiac engine
or does it have to be for a pontiac?
I know I have to watch the end shaft lenth.
Thanks John

A chevy bellhousing will not bolt up to a 350 Pontiac engine. B.O.P -buick, olds, Pontiac bellhousing will interchange. Muncie and super t-10 will bolt up to most any of the chevy or B.O.P bellhousings. The trans crossmember your powerglide uses is also the one you want for a 4 spd. Your second question- only a 350 B.O.P trans will work.