If it were my truck, I wouldn't have stuck a Datsun inline 6 in it, but I'd be apt to put a BMW inline 6 in it (or whatever else I have on hand) - triple the horsepower, raise the redline by 2500, and get better gas mileage. The main thing is that I'd still be driving it, that's what being a 67-72 truck enthusiast is about to me, anyway.
But I like the 292 for what it is already, and I'd like to keep it so I can haul stuff or tow a trailer sometimes. That being said, if the 6 ever dies, I've got a Dodge 360 just sitting that runs great that would be a good transplant candidate (for the money, it's free) that could tow about anything. Can't hardly sell the Dodge engine for anything, so I might as well use it?
Anyway, here's my short list:
you could tear it down to the frame and wait 5-10 years until you get the money to put it back on the road
you could stick a gas hungry engine in it and never be able to afford to drive it
worst of all, you could obsess about what another man has under his hood
