I have the 68' 4-speed cam in my 69' 4-speed Dart. It runs well, with a nice thump. Don't forget the Thermoquad carb needs the later intake, as a 71'. I had the 3.91 and sold it but went back to the 3.23 as a street driver. It all depends on what you are looking for in a application. No maybe on the headers, do it. It's all in the package.
