Biggest problem? Eventually turned out to be ignition, although I spent quite a bit of time going through carb/intake (both new) chasing what I thought was a vacuum issue causing a rough idle. All said and done, it was ignition. I finally put another new distributor cap and rotor and it immediately started running smoother. Vacuum at idle came right up to 18. In the mean time I got the choke/ fast idle on the new Weber working correctly along with a few other loose ends tidied up.

I did go around my elbow to get to my thumb, so to speak, but I'm really pleased with the result, finally.