I think all blocks (not actually all, but..most of the ones talked about) are the same exterior size on pontiacs , unless you go waay back or talk of the inline 6....
the answer is no, you cant use a Pontiac motor mount for a small block chevy...or a big block chevy even though just about all Pontiac blocks would be considered big blocks...326,350,400,428,455 all same exterior size, = bigger than small block chevys
and w a small block chevy , you`ll get lots of space in front of the engine...
Besides, if I were you,I`d stick w a Pontiac engine... my 0.02
