I know it was an option in 1970. It was a 330 horse 383 4 bbl. not a 335 horse 383 magnum; even though it is an N-code. I believe the code for the engine is different on the fender tag. The car had a 383 4 barrel emblem on the fenders by the Challenger script. I do not believe it was carried over to 1971. Someone will know.