OK, most of my cars are /6s, but my driver is a 273 Commando car. Anyway, I rebuilt the stock AFB, set to specs, and it seems to run pretty good except for the following. It seems to run rich at idle, and floods itself when warm. The carb had been rebuilt in the past before I took it apart, but it didn't look damaged or anything. My guess would be the float setting is too high, but I checked the setting twice, and a professional mechanic checked it too. --- it's right on. Is the current fuel less dense, meaning I should set the float lower since it would be sinking a bit more? Any other ideas?

-With todays fuel, the needle / seat needs to be in perfect condition.
-Try to insulate the carb from excess manifold heat, is the heat riser valve working well?
-I tend to add a fuel pressure return line so I can bleed-off fuel line pressure after hot shut-off. Look at newer cars in the junkyards for the parts or get a fuel filter with a vapor bleed side fitting to have an exit point.
I have also drilled a small hole (.020 max) in the fuel pump chamber wall, this makes a small "port" connecting the high and low pressure side. The pressure on the high side bleeds back thru the port after shut-off.
DD

I like your idea of bleeding off pump pressure, and will follow up on that. The heat control valve is NOW working well. For some reason, the previous owner put the spring in backward, and the valve was open when cold, and closed as the engine heated up. Sounded like a clapper on a bulldozer when warm! Sorry I have to admit this, but I don't quite understand the bleed hole concept. ---- Stike that ---- I reread your post --- I was thinking accelerator pump, not fuel pump. What you say makes sense.

Sorry for the "short" discription...
As for that fuel pump modifacation, that only works on pumps you can dis-assemble. (Carter type pumps)
Adding the return line is a better way to go but it's more work.
DD