The easiest swap would be a 53 with Powerglide out of a car, or any 54/early 55 (car or truck), due to water pump located in the right place.
The late 54/early 55 will have the large journal camshaft if you have a notion to add a high lift cam.
All of the engines I have mentioned are insert rod bearing, full oil pressure engines. The 53 Powerglide engine came with aluminum pistons and hydraulic lifters.
You could learn more about this in my blog, except that I don't have one.
Carl
