[vince1]

I think I would measure the cam lift on each individual rocker just to rule out the possibility that a lobe could be beginning to wear. I'd also set the valves with the engine running. I found mine a bit tight after following one of the suggested methods prior to it running.

I've had a really old corroded up cap on the 250 HEI. It didn't seem to bother it at all. More likely could be a plug or wire off a bit. It's a bit of a hassle but did you try removing plug wires one at a time?

If it doesn't like to rev hopefully a little more advance will fix it. On the other hand I have noticed on my 350 that it doesn't like too much advance. It revs really nice to a certain point and then doesn't like it at all. Most of my timing is by ear though and I feel that after 3 or 4 tries it gets pretty close to optimum.

I hope you get it running well. I see one out in Canmore with a well drilling rig on it. Another is parked next to the highway with a sign advertising trees. It's nice to see the old big trucks still being useful.