JoHan did the NASCAR version first based off their Promo of the 72 Gran Torino. They cloned the body of the promo but put a flat hood which was rarely used in a 72 NASCAR Cup car.
MPC tooled a 1972 Gran Torino for their NASCAR series. I do not have proof that MPC cloned the JoHan body but ALL body parts swap between the two bodies. Hoods swp perfect as do bumpers and glass. The MPC is the better of the two as the JoHan and AMT rebox have all the stock trim and emblems in place.

box stock MPC issac kit I built while working for Model King and AMT. We did some resto on the kit and new decals. Each kit had 4-6 options for decals. Thanks
Richie Panch