I'm getting an 86 K5 in a week or 2 from a guy that always comes into my store (I work in Auto Parts). It has a 3" body and 4" susp lift on it. I will be pulling out the body lift, but staying with the suspension lift. He thinks the drieveshafts need to be lengthened an inch or 2 each from the lift, but they are on there now and working. When I get it I'll see whats up with it, how the yokes are sitting on the slpines etc but I was wondering if there is any specific measuresments or formula I could use to determine the correct length. The truck was originally a 5 speed, but I sold him a POS rustbucket 78 a few years ago. Out of that he took the trans, case, rears and whatever else was needed to swap to an auto. So, it's basically got a 78 drivetrain. What options does that leave open as to what rears/case are in there? Im pretty sure the trans is a turbo 350. One more thing, how hard is it to lengthen the shaft? My dad runs a sheet metal shop and he's very knowledgeable and experienced in what he does. He also used to own a K5 so he's familiar with them. I would imagine he just has to cut the shaft, roll a piece of steel to the appropriate length/diameter and weld it in straight, correct? I haven't asked him about it but I'm sure he'll be able to do it. PS I did a quick search about the driveshaft but didnt come up with much.