grabbatire........NO....NO....NO......the "infamous ballast resistor" is a special kind of resistor that changes value with heat. It starts out about 0.5-ohms and as it heats up (inna'bout 2-mins) it INCREASES in value to about 2-ohms. This is something you can NOT measure with common ohm-meter. But you can measure the effect on the top of your 1-terminal squarecan ignition coil with yer VOLT meter. Ittza LAW, Ohms Law.
The "infamous ballast resistor" is like yer lightbulb, it either works or it don't. So iff'n yer tractor starts, guess what??? Yer ballast resistor is working. .........Dell, yer self-appointed sparkie-meister