to get around the 1HP per cu in rule, wikipedia says Chevelle 427 SS were sold on Indian reservations

There were 1968 SS427 chevelles sold on Indian Reservation's territory to bypass the GM rules that prevented a car from having more than 1 H.P. per 10 pounds of weight limit (exception was the Corvette).

https://en.wikipedia.org/wiki/Chevrolet_Chevelle