1973 Disc Brake conversion / SBP / 14" narrow steel wheels

These are drilled for 4 or 4-1/2 inch BC on the same rotors and hubs, but requires an inner wheel diameter of 12.92 inches. It would allow for upgrading wheels in the future, if need be. I don't have my spare wheel handy to measure at the moment but this may be your best option, as it uses the factory six cylinder spindles.
1973 DODGE DART Wilwood Front Medium-Duty Disc Brake Kits 140-2719-B