Thanks, Frank - then, you have answered his question.
I'll add:
1954 and later 235 and all 261 engines would be more modern engines, with the higher pressure oil lubrication system.
1954 and 1955st series 235/261 would be the easiest swap, because 1955nd and later 235/261 engines would require the
relocation of the water pump.
The 1953 or earlier clutch housing will need to be used to fit the 1953 and earlier motor mount crossmember with later 235/261 engines.
I'd used the 1953's standard-equipment rear-transmission mount on that earlier (1953) frame crossmember (
that cross member was not used/needed on 1954 and later trucks).
