Iron Duke or Odd Fire Buick V6?

I have a 225 odd fire in mine , came stock. They are torquey little motors. Compared to the 258 I had in my 73 cj5. The one draw back is , a lot of mechanics haven't worked on them, so unless you're doing your own work, that can be a challenge. Plus sometimes it can be a little more work getting parts for them. HEI makes a world of difference, instead of points, also. Good luck, to you, and enjoy.
Years ago, I heped my dad drop a 327 ci Chevrolet V8 i to a 1959 CJ that originally came with the 4 cyl. We kept the original three speed manual transmission and transfer case, and added an over drive. The combination worked amazingly well with no drive train issues at all. The extra HP of the V8 was a game changer.

Looking back now, it would have been nice to have full fuel injection or at least TBI, but we made due with a conventional carburetor.