.............I knew what the difference was/is.........i'm just saying i have 3........1 is on my 40,000 mile 75 duster with #s matching everything, i had no reason to check the air cleaner as the rear end, 727 tranny, and motor carb,intake #s all matched. 1 i got on my 74 duster that i changed to a race car, and the other came with a 75 dart sport......all cars are factory 360 hp cars, `1 auto, 2 are 4 gears......over the years i gues anything can happen........kim.......