Ford V8 ignition resistor question

[Bruce Parker (RIP)]

I gave my carrier a good run today and it's doing what it's always done...quit when it gets too hot. The rad and timing is OK and I think the problem is in the ignition resistor. I have the original early clam-shell distributor and a Ford 'F8 tractor' resistor in the dash. Starting from cold is no problem. Once warm (hot), the ignition resistor gets too hot and prevents current from getting to the coil. If I jump the resistor, the coils gets too much current and runs too hot. What the frig do I do to fix this???