My buddy had a 360 (in his '65 A100 truck) that ran well until it warmed up (15-20 minutes). After lots of investigating I discovered the harness to the Electronic Ignition module had been pinched/smashed when the engine was installed (by the previous owner). I made/installed an overlay harness, to the module, and the problem was gone.
Okay... Thanks for that, I will check it, however, seems strange that after approx 10k miles and coincidentally after the carb got refreshed that the problem surfaced... See how we go!