Remember as a kid working in a gas station and a customer's 55 Chevy with almost identical problem.

I discovered pulling vacumn hose all was well. Pulled distributor cap, wire going from coil to points was broken inside. Advance plate would move far enough with anything above 1500 rpm,,,pulling wire apart. Repaired wire all was well.

I however agree more with more initial advance requirement,,,but lack of should not create a misfire slobbering all over itself.