Better to have the original engine rebuilt.

I know that a 54 235 will bolt in and replace the 235 in a 1946 2 ton truck.
Then all the small things make it not worth it when you have the original
engine to rebuild. My son had to change throttle linkage, oil pressure
gauge. Lucky I found a NOS GMC oil pressure gauge. Then the 46 had
an 11" clutch, but the 54 flywheel ran 10" clutch. The new clutch works
ok but will it stand up as well who knows.

It is not can I make it fit.
Not even is it a direct bolt in.
What it is that even if it is a direct bolt in there will be so many things that
will not be found out until you start and then after spending a lot of
money, it is hard to change course and throw all that money away and
go back to keeping it original.
Jeffrey