Ultimately, the Ford 427 itself was never banned from NASCAR. Only variants of the Ford 427 weren’t permitted to see a circuit in 1965 due to changes in engine regulations. Leading up to 1965, both Ford and Chrysler had built engines for their cars that didn’t fit in with NASCAR’s stock car rules. The Ford 427 high-riser didn’t fit under the hood of the factory Ford Galaxie, so it was prohibited from competing in 1965. The 427 SOHC Cammer was also banned due to the fact that it was a special one-off variant that never made its way into road cars.