Will a 400 diesel rear and tranny swap with a 1953 SM? Thanks...

The SM engine will bolt up to the 400 at the bell (clutch) housing.

That would give you a "poor man's" SMTA.

If you split it any further back than the bell housing, nothing will bolt together AFAIK.

The 400 rear end will make the tractor a few inches longer so you may need to modify a few things on the steering column.

I was going to do the same thing,but decided I had tomany other projects in the works!

If you put a 400 clutch & pressure plate on the SM engine everything forward of the clutch housing is a bolt on. Use the SM front fuel tank , steering suport parts and your good back to there. Problem, 400 transmission top cover doesn't have the bolt holes to mount the rear steering support pipe, rear fuel tank support or part of the mounting holes for a live hydraulic reservoir if used. Modifications are needed, or put the SM trans. top cover on, but to do that SMTA shift forks need installed to cover. There not laying around everywhere. If you have a live hydraulic reservoir and mount it, the rear gas tank support just needs moved to the other set of holes to mount fuel tank. if not a plain rear tank support will need more length added to front. longer rear steering wheel shaft is needed, SMTA or 400 works. Steering support pipe needs to be 3/4 inch taller than your SM to line up correct. If a plate is made to bolt it on a 400 cover it gets raised then. 400 shifter will need modified. If you have a stage 2 SM with live hydraulics (probably what you have to have hydraulics after change) hydraulic hoses, throttle, choke, and starter rods need to be longer. Battery cable and some other wireing also.