Dave, that is so funny you said that. My neighbor calls it "restoration creep".
That's exactly what happened to me. It started with headers and dual exhaust. That project turned into cleaning up much of the engine compartment. Then came the O.D. After that, radials. Next, HEI and then suspension rebuild. And now, we're about to begin assembly on a 261 stroker with all the goodies including built up head, mild cam, dual intake, etc... Next in line, disc brakes. I don't think it will ever end.
At 1st, I wanted to do everything at once. My neighbor talked me into to one sub-project at a time. I'm glad he did. I get to keep using the truck with minimal down time, not to mention a clutter free garage - sort of. The other benefit is you get to experience the upgrades one at a time and you get a good idea about the improvement each one gives.