How confident are you that your '73 440 is OEM and hasn't been modified by someone, somewhere, between the factory and you?
Is it CARB or non-CARB?
My '69/70 M300 and '77 B200, both with 318 engines, had single ballast resistors. The '77 was OEM as I was the first owner and hadn't modified anything to do with the engine. Can't say the same for the '69/70.
'77 was definitely non-CARB and (I think) '69/70 predates CARB.
If I get a chance tomorrow, I'll wander down to Junior (the '72 M375) and take a look ... same with the 'donor' Dakota.
