Case 530 TLB Point Gap?

[AV8R62]

A "ballest resistor" will make them last longer
however it can also make them hard to start.
and that can be fixed by replacing the starter solenoid
with one that has the second small terminal on it (if if doesn't already have one) that terminal will send a full 12V around the resistor to the coil while the starter is engaged

 

[normde2001]

I believe I would get after that distributor bushing or a new distributor. The points are probably arcing excessively due to bouncing when opening and closing, because of the wear.