Probable advantages for each:

Keeping the 216 -

The truck will be worth more money if you (or your estate) sells it.
The truck will appeal to a larger universe of buyers if above
The truck may be showed in even national shows as original
The cost will probably be less than installing a 235

Installing a 235 -

The truck will have a few extra ponies.
The 235 may be somewhat more reliable.

And remember, if you install a 235, the people that like the non-original swap will ask you why you didn't install a 261.

Make yourself happy.

Jon.

Good carburetion is fuelish hot air
The most expensive carburetor is the wrong one you attempt to modify.
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The Carburetor Shop