Is there a way to bench-test a points-type coil? I'm thinking some erratic surging is not a fuel/carb issue, but might be ignition-related after all.
I can swap-in a known-fresh coil, but I like the old school hot rod looks of the Voltmaster, a 5 x5 square of mean black bakelite, jutting out off the block.

you mentioned being able to swap a none good one do that if it fixes your problem than you can go buy the one you like after wards i was in the same boat and did just this

Well I swapped in a different coil. It started OK, but I still have the surging gripe. I think this is a manifold /suction leak. It cycles thru 1300 to 2000 rpm and back again. I can't get it to set up stable. Turning the idle/mixture screws does nothing. So it's not an electrical problem.

Sounds like a vacuum leak. To locate, take an unlit propane torch and run it around the intake. The engine should speed up when you hit the leak. Some people use spray carb cleaner.

I'm assuming this is on your 292, notorious for intake leaks. If so, and you replace the gasket, the best cure I have found is to install the manifold to head gaskets with ultra-copper RTV. A bead on the manifold side, allow it to cure for 20 minutes before installing. Then torque the bolts, let the engine sit overnight before starting.

Fred you may have hit the nail on the head. Yeah, it's 292 teething problems. I tried a new gasket, but obviously it didn't go on right. I got about half a block into my test hop and it went bad on me. Had to haul it back to the house with the GMC.
I had sprayed a Clifford header gasket with Permatex copper spray- a -gasket on both sides. I'll have to redo the gasket. If this new gasket isn't toast, I'll try the bead of Ultra Copper RTV trick. In the old days we used to use double gaskets.
Thanks.
... Funny, I thought this was the Electric Forum?