What will cause slight miss idling on a 65 170?

I've got the backfire through the carb situation taken care of it seems. I believe it was a carburetor gasket with a vacuum leak. I installed a new gasket today and I was able to rev up the engine with no more backfiring. It starts fairly easily seems to have reasonable power but I just drove it around the driveway no more than 20mph since it's not tagged yet. Sitting there idling after it warms up for about 5 mins you can feel a slight miss every once and awhile. I've got everything adjusted and tuned. It's got new plugs, wires, cap, rotor, coil, air filter. The distributor/points/condenser, carburetor, fuel filter are all a year or a little more older. I don't know if it's a choke problem, dirty fuel filter, or ignition problem. I don't even know if it is a misfire but it seems like it's got a little very slight shake on idle. But it's almost a 50 year old engine, no telling if it's ever been rebuilt, and how long it was sitting up before I revived it a couple years ago. Is there any kind of top end cleaner that I can safely add to help free up deposits on the valves? I didn't want to dump any seafoam down the carb. Where do you find a new choke thermostat for this 1bbl holley? I think a lot of issues I'm having with it warming up is with the choke thermostat.