Thanks for the input and I agree with your comments.
I wouldn't call the idle good, but it will idle at 600 with some misfiring. Floats have been checked and rechecked. I have new CM needles from Moss. They are stamped CM, but I haven't measured them against the SU specs so it's possible they could be out of spec. I can borrow a micrometer from my son to measure them.
Today I received a new timing light. (Broke the old one) and was able to measure spark advance. The goal is to compare my advance curve to what the distributor should exhibit. I thought this would tell me if the centrifugal advance was working properly and hopefully something about the vacuum. While running the test, I noticed that the misfire seems to be associated with number one cylinder although I didn't test other cylinders. I'll need to put some other marks on the pulley to check other cylinders. While watching the pulley with the strobe on, I could witness each misfire. Number one plug fired well for five or six times and then it fired early. The early sparks would show up about one inch (on the pulley) btdc. each time I heard a misfire. I'm trying to understand what could cause that. As I've mentioned before the cap, rotor, and wires are new. I examined the cap, and it looks good. I checked the number one wire with ohm meter and tightened the spiked screw a little, but the misfire still exists.
I've attached a spark advance curve generated with the vacuum line connected. I was going to repeat the test with vacuum line off, but the engine overheated, so I'm waiting for it to cool. I'll test some more in the morning. If you have a good source of info for advance curves for the distributor, please let me know. thanks, Ken