Found it,r was used for points style ignition,once hei came in,no need,so 73',74' was the change,my book showed stand alone coil,which is wrong,they used a picture from previous years

 

The resistor was for hei, points didn't need it. The thing "back then" was burning up coils with straight battery voltage all the time, zap the coil with full battery voltage during crank, then cut it back after it starts to save the coil. That is old hat even back in the 70's we just ran straight power to the coil.

 

There are coils that do not need the resistor. The one in my 49 chevy has it printed right on the coil.