400 into a 74 Duster Which Exhaust Manifolds

Yup yup. THe C body mannyfolds fit good. If you go with the C body HP manifolds, the driver's side may need to be angle milled on the head port side to make the outlet angle in towards the motor. I think the amount is like 1/16". Other than that, they drop in.....and some drop in with no mods at all.