I can't really make any recommendations for tranny's. I'm still running a granny-low 4 speed in my 3/4ton. I was just thinking that with the weight of the rig alone may have an impact on the durability of the T5, but perhaps if you babied it it would work okay. I simply don't know for sure. As to what will bolt up, most anything after '62 that has the standard GM bell housing will bolt up to that 327. There is a lot of stuff that will mate up with no issues other than getting it mounted in the truck.
As for the engine itself, you may have to get a set of V8 towers to put the 327 in. I don't remember how the 235's sit, but that would be the worst part of it. Make sure the mounts line up on the motor and slap it in.
