Help! Hedders for a Duster W/1 7/8" tubes on S.B. With R/T heads??

Thanks Adam, I appreciate your help. Now if I can find someone with a Duster using that number on a magnum. The techs said the flange might leak on the two middle ports.??? I know a guy with this engine in a 65 Dart that was dyno'd, and he said it likes the bigger hedders, he uses the 75110 and likes them, they are 1 7/8", fender well exit.
Chrysler also recommends the 1 7/8" on this engine. 360 magnum stroker,
402 C.I., 435 H.P..