This will be a long story, im usin sanderson shorty headers, 1 half from one set and 1 half from another another set, i believe they are 1 3/4 tubes, with 3 inch collectors. i machined a 3 inch pipe into the 3 inch flange, bought a 3 inch pipe set up from jegs or summit, i also ordered 2 3 inch mufflers from e trailer, i believe they are motor home mufflers about 30 inches long, they are quite enough, i also had to remove the 16 gallon plastic gas tank on the drivers side, so i could get a 3 inch pipe thru that portion of the truck. i found a 32 or 36 gallon gas tank at Lmc ford, with a kit to mount in the rear, where the spare tyre goes. now i dont want to try and run hot exaust next to the fuel tank, and i cant even run the pipes over the diff because, its too close to the tank, the fuel line was changed to steel line i piece from the tank to the mechanical pump. i also ran my return line there also. its well protected inside the frame rail. used aircraft style edel clip rubber against the line, galvanised steel line. but gettin back to the exaust, i have 2 choices neither are good. run them out the side in frnt of the fender or turn them straight down, which will realy drone, i have no desire to listen to a hot rod muffler. im to old! there are 3 styles of zfs and 2 types, the big one i got first, had a bigger input shaft for diesel usage, then the ones that fit the 385 engines, and the other that fit the 5 and 5.8 and 4.9 engines. i have 3.55 gears and start out in 2nd on a hill and 3rd on flat grnd. emty. id like to stay with this 5 spd but an overhaul is half the price of a new tremec that can handle 600 plus ft lbs.my son has a nova with a bbc 460 cu in with a tremec. nice trans.gw