Hedman makes great weld up kits for Mopars with tube chassis or fenderwell type headers.Plenty of different universal bends available there too. I opted to buy, in addition, a set of flanges with 2 in.long stub tubes already welded to try to avoid the warpage issue and pipe/port contouring on my first try. That really paid off well.I only built my own headers because I wanted 2 1/8" primary tubes that were shorter in length than the Hooker fenderwell style I originally had.For all the work involved vs. the return in performance, you might just look at Hooker and Hedmans fenderwell shelf offerings unless you just desire the project of building your own set. Their sizes should be right for a 600hp engine. Bill