[V8 Bob]

I've done some research based from written material on hand, namely Ford shop and service manuals, and think/hope the results will answer some of the questions on this post about coils.

Ford V8 6V systems used ignition resisters inline to coils up to '48. I don't have any resistance values from '32-'38, just schematics. 1939-'48 coil primary resistance measured .47-.51 ohms, and although I could not find the inline resistance value, pretty sure it would be around .5 ohms, for a total about 1 ohm, based on......


6V Fords '49 through '54 used coils with primary resistance of 1.05-1.15 ohms with NO inline resistance. I don't have info on '55s but would think they're the same.


In '56, Ford switched to 12V, with inline coil resistance of 1.3-1.4 ohms and coil primary of 1.4-1.5 ohms, giving a total of about 3 ohms.


1957 was the first year for an ignition resister bypass built into the new style starter solenoid, where the 1.3-4 ohm inline resister is bypassed to to the coil while starting, but allowing the same 3 ohm total coil primary resistance when running.


I don't know the specifics on why 6V system coil primaries were just over 1 ohm and 12V point system coil primaries run/ran around 3 ohms.


Bob