I'd like to think they didn't cheat. Idk. Lot of development going on then. GM's DRCE was and still is THE platform. NHRA, as per usual, wasn't going to let GM look like clowns for too long getting beat by Mopar. Regardless of sponsorship. The Mopars even ran an identical GM based engine, but, still didn't run as well. I think with Pro Stock, with drag racing in general, the hey day was in the beginning. When it was line up and run. "Before the dark times. Before the Empire." .......
