Just quickly some info to the 261. It is a (supposedly) rebuild engine that came with my 1953 1/2 ton. The 261 has no oil pan, but single carb intake & standard exhaust.
I need to check this engine over completely, bore, crankshaft & connecting rod bearings, leak-down test etc., to see if this engine really is 'rebuild' or if someone stated what is not true. New paint doesn't make a rebuild engine.
Jerry's idea of a AMC/Jeep 258 Carter YF sounds to me the best way for my use, I am not going to race this truck.
I have gotten a lot of info here and need to digest this all and check clearance under the hood & needed modification.
A quick search shows many options and I will only example one here:
258 Carter YF sample