[poff]

Irrelevant. I have unknown aftermarket front springs and stock rear springs with a shackle flip and they work great. There are so many variations of applications for springs they would never be the same from truck to truck. When you order a set of springs for a 3/4 ton 4x4 from one manufacture they are all the same but you may never haul stuff, someone else may have two extra tanks and a tool box and haul dirt all the time; no bumper vs my 150lb bumper; wood bed vs metal bed. It's all trial and error, even if you have a matched set.