The engine swap is not quite simple but many have done it.
I think a later 235 or 261 would be a better swap, more original appearing, plenty of power, less work.

The 14 bolt rear if from a dual wheel cab and chassis truck, not a dual wheel pickup truck, should be about perfect width to swap, measure and see. Likely need to move spring pads on the axle though.

Grigg


1951 GMC 250 in the Project Journals
1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-