If by any chance, you still have the tire label inside the driver door, (just below the striker post), the tire size that the car came with will be written on the label. Doesn' t say what wheels, but you' ll know if it came with 14'' or 15''. Friend of mine owned a 440-6 '71 'Cuda and it came with 14'' X 6'' rallyes from the factory. Sale code for rallye wheels is W21, but I' m not sure it's listed on the fender tag. hop that helps.