Closest would be 1972 when Mike Fons won Pro Stock in a Dodge, and Petty won Nascar in a Plymouth. '71 was Ronnie Sox in a Plymouth, and Petty in a Plymouth. 1970 was Sox in a Plymouth, and Bobby Isaac in a Dodge.

EDIT: Richard Petty won in 1974 with a Dodge, and Larry Huff won AHRA with a Dodge.