The Doug's on my '76 Duster didn't need anything, fit like a glove. However, the Doug's on my '74 Duster needed the #5 & #7 pipes massaged in the exact location as the OP's, by the drivers side torsion bar. But, it has the /6 to V8 schumacher conversion mounts and I perhaps didn't get it set exactly like factory. Didn't bother me a bit to put a little relief in the pipes though.