Classic over carburetion problem?

Don't start throwing parts at it yet. Like suggested, check cranking PSI. Might as well check all cylinders while you're at it. They should be very close.

Timing is a big thing. I believe earlier in the thread you said you adjusted the timing to get rid of ping. If so, get a timing light on it (connected to cylinder one, the front driver's side plug wire) and see where you're at. Not enough spark advance could very well be your problem. YouTube how to check and adjust timing. Mine is happy at 36 degrees total advance. This is NOT initial advance!! You check total advance with the engine at a relatively high RPM.

If the engine pings with spark advance set correctly, you need better fuel.

Do you have the stock distributor? If so, there is a vacuum advance on the distributor. Is it connected to the proper port on the carb? Pictures would be useful.