I don't buy exhaust kits any more. My stuff and what I work on is rarely stock, and therefore there is no sense since I will be cutting it up and modifying it to fit anyways. I typically buy a bunch of stainless 180 deg. mandrel U or J bends and cut the bends I need and weld it back together. Just finished a complete exhaust system for a '60 T-Bird. FPA headers, and all stainless 3 inch tube after that. The only "catalog" headers I have purchased in the past 10 years came from FPA. I did purchase a 3.5" Banks kit for my '85 F350, still had to modify the down pipe coming off the turbo, but the rest fit pretty good.
If the bumpsides are anything like the '76 Dentside F250 (last of the 390's) I did a few years ago, it was very easy. Mostly straight pipe and just a couple of bends. Brought the drivers side over to the passenger side and ran both pipes parrallel down the passenger side. Used a pair of "truck" can style mufflers and exited the pipes right behind the rear wheel. It looked stockish, but definitely did not sound or preform like a stock system.
