Can't help ya on the trans questions...but that early 360 will have extra thick cylinder walls, and should have J heads.

The '71 - '74 or so 360's came from the factory with the 340 water jacket core, meaning the walls should be roughly .020" thicker than later 360 blocks. 340 bore size = 4.04"; 360 = 4.00".

I pulled some J's off of a '72 motorhome once, & both of 'em were cracked. It had probably overheated at some point in it's life.