I have a 71 Challenger with a 440/727 and had Idler Arm/Pitman Arm and fast ratio steering installed from Firm Feel (California). Their website lists header-brands that do and don't fit; after making some calls I am leaning towards buying Hedman headers (part #78038). Does anyone out there have the same set-up and, if so, what headers did you choose and did they fit without having to take a hammer to the headers, etc?