3/4 ton crew cab long bed to 1/2 ton crew cab short help

[dragn91]

Picking up a new beater truck it's a 1980 crew cab long bed 2wd c20. I want to swap out the 3/4 ton suspension for 1/2 ton mainly to improve gas mileage because I'm sure the current rear has a low ratio and I need all the mileage I can get out of that 454 400 turbo combination. I also have an f450 diesel so all my heavy pulling will be done with that this will haul the occasional load of scrap , hot rod parts etc.. mainly need to get out of this minivan but still have room for my growing family. I'm no stranger to welding and fab. But this trucks getting done on a budget over the next couple years mainly trading for parts not buying. I'm looking for info on the half ton conversion my main questions are will half ton spindles go right onto 3/4 ton ball joints without a problem? Or will I need to swap the control arms also. I'll probably just cut off a coil or two to get it sitting better and flip the rear or make up some lowered shackles and hangers both I have done in the past but never on a square body. As far as the rear goes will a half ton rear slide right in and bolt up or will I have to move the perch mounts and shorter or lengthen the drive shaft? If I need to shorten the drive shaft I'm going to wait unit the short bed conversion to change the rear out. Also wondering if there's a way to use a 6 lug rear and front somehow I have a set of crusty Boyd cottington 20s I got for free I'd like to use if I can after stripping them and powder coating or painting. Last questions are how much and where do I cut for the short bed conversion the beds the worst spot on the truck rust wise is why I'd like to convert it but if I find a decent long bed I may still keep it haven't 100 percent decided on it yet. Sorry for all the question I just need to get my ducks in a row with two kids and 3 jobs not much free time lol