Your wrong , I just measured two cars on rotisseries that are here . Dusters are 1 1/2 inches wider, 3/4 per side then barracudas. with factory quarters . I recently had wheels made at wheels vintique 4 1/4 backspace they just fit under the barracuda . The 4 inch were tight on the barracuda. the 4 1/4 gave just enough clearance.
From the inner wheel house to the outside of the quarter barracudas are 13 1/4 Duster's are 14.