The original lucas coils were internally "resisted" and this type is the only correct one. If you buy an aftermarket coil i recommend u ask the store if they have that kind of coil [internally "resisted"] if all the have is an externally ballasted coil then you'll want to but a ballast resistor that's compatible with that coil. Your engine will run with an externally ballasted coil but it won't be long before your points rubbing block will melt