Just got my first slant six

Next problem...

Now it started having a rough idle once warmed up. The alternator and ignition module are about a year old. The carb was rebuilt last year. The plugs are only a few weeks old. I thought the plug wires might be bad and I knew the battery was weak.

Today I replaced the battery, ballast resister, coil, cap, rotor, and plug wires. It started right up and purred for about five minutes the stuttered a bit and died. It starts every time but dies if I don’t keep the RPMs up.

Removed air cleaner and no change even though the filter could use a change. The choke was wide open, not closed.

What are the possible causes of the rough idle and stalling? Air/fuel mixture, timing?