OK have a 51 3600 still in the planing stage as far as engine and trans
Originally I was thinking useing the 250 six out of a 74 1/2 pickup rolling frame I picked up for donor parts
So 250 with the trans off the 216 that the 51 came with.

But traffic around here has become so congested if I’m honest I will use it more with an automatic.
Problem is I know nothing about automatic transmissions and what will fit what block

So what would I be looking for automatic trans wise?
I don’t have a torque tube to worry about
Not going to be a high HP situation
Usage will be as a light pickup needs to be able to do about 70 -75 with out screaming
Small block V8 isn’t totally out of the question.
But I think the six is an easier for me with the straight front axle .
Junk yards around here don’t have much really old stuff and what they have they want real money for it
Preference would be something I could get from a rebuilder.

Fenders and inner fenders are done and painted, cab isn’t done yet so firewall and or floor mods not a big deal

About as high tech as I want to go is I will probably go with a throttle body fuel injection kit