I put a 350 with a TH400 in my 1937 1.5 ton. I took the motor mounts and mounting perches off an early 80's chevy 4x4 and welded in some plate steel to make them fit. You will probably have to notch the front crossmember to make the 350 sit correctly without modifying the doghouse. And you can get the trans crossmember out of Speedway that you will need ($80). Its a universal that you can cut to fit. Just measure how much drop you will need first (when you mock it up). I went with a aluminum radiator and electric fan for cleance (not enough room to run a flex fan) and a framerail trans cooler.
Good luck!
