Redfish: Thanks for your reply. I did remove the top immediatly after shutting down a hot motor, and the fuel bowls appeared to be a little less that half full. This looks like a good level, and doesnt overflow into the carb throat.
I do not have any hooks from the floats to the needles. I have seen them before on other carbs, but there are none on this carb when it came back from the rebuilder. I do have them in my box of original parts from when I rebuilt it last year. Incidentally, the only reason I sent the carb for a professional rebuilt was because the idle mixture screw broke off (it's a left hand thread) and the accelerator pump passages were blocked from 23 years of sitting. Both issues were corrected.
65Val: I did consider the heat from the exhaust crossover. There is only a thin paper gasket between the carb and manifold. I'll try a spacer next. Do you remember what size worked for you? How did you block the crossover? Did you remove the intake and plug it somehow? My heat riser on the passenger exhaust manifold has a broken spring, so last year, I wired the counterweight in the open position and verified by looking into the manifold to see that it was open, and not wired closed.
Thanks for your help, I'll let you know how the insulator works out.