Guy in facebook in the Chev GMC 47-54 forum has a 305cu in V6 just pulled out of his truck runs great $500. Not a bad way to go either IMHO

1953 Chevrolet 3100
261 cu inch, sm420, 3.55 rear, torque tube still,omaha orange, still 6 volt, RPO green glass, side carrier spare, all done
In the DITY Gallery
Video of the 261 running

1964 GMC 1000
305 Big Block V6, sm420, the next cab off restoration