trying to pull ponnies with little cash

As far as headers and exhaust go, I did a Summit racing exhaust (@ 2-1/2) and hooked it to Hooker headers Comp's, though, with minor work, you could hook'em to any typical 1 size fits all header like the Hooker.

http://www.summitracing.com/search/.../PLYMOUTH/Model/DUSTER/Year/1972/?Ns=Rank|Asc