If you weren't so far away I'd take the 292. They go for $400 around here, the farmers use them for irrigation pumps.
As for your engine, it's not a drop-in, but not that tough. Bell housing is the same. You will need motor mounts. Carb linkage is different, depending on the year. In 71 GMC switched to a cable instead of the rod. Switching the isn't that hard, you can either buy used or a new Lokar pedal and cable.
