[dsraven]

it would help to know what the pontiac diff is from. it is like saying your other car is a chevy. there are lots of chevys. haha.
what does it come from
what gears does it have
is it a posi
what is the wheel mounting surface to wheel mounting surface dimension
what does it have for brakes
do you have a history on it (gramma's car or it came from a street racer)
have you pulled it apart to check axles, bearings etc
have you checked parts availability for the basics, like a re bearing kit or an axle