Just need to know if this is worth my time. I got a free 9" rear out of a lincoln. Its got 28 spline shafts and i believe its the big bearing axle. What is needed to convert this to 31 spline. Any help would be great. Thnaks

You do know that the lincoln rear's had different lenght shafts, the best way would be to find a ford truck rear (cheap, and commong) with 31 spline (most 4x's but it only takes a few minutes to pull an axle to find out), 76 - 82 i belive are the same shafts, and would be what i would get, then swap the spiders into your 3rd, put the new 3rd into the truck rear and you are good to go, but if the lincoln rear has disc's just swap the discs to the trucks rear (easy to do, axle flange needs to be turned down though) and be sure to grab the mc and p-valve from the lincoln, then you are good to go with a new rear and disc brakes.

Yes and no. Most truck 31 spline shafts will be a the same length both sides, so they will not work in the lincoln. Most of the narrow style 9" axles that are same width as the lincoln are also 28 spline. You could get aftermarket shafts.... but that kinda kills the benefit of a free axle.

Check the lug pattern on the lincoln. It is probably 5 on 5, rather than the 5 on 5.5 that most trucks are. So to use the disks on a 31 spline shaft will require turning or grinding down the axle flange to fit the hat and redrilling the disk to 5 on 5.5. This starts getting to be a PITA.

Your best bet is to run the axle as is, with different pattern wheels than the front (yuck, IMO, for what that is worth) OR just pick up a 31 spline out of a truck. They are a dime a dozen (well not really 12 for ten cents, but they are real cheap). If you want the narrow width, look for an early bronco 9". It will be similar to the lincoln in width and will be 5 on 5.5. 28 spline also, but still pretty hardy. More ching though.

Actually you use front 4wd rotors of the 80-96 trucks- then just spacle the caliper bracket out a bit, the rotors are spaced the same and the thickness is close enough to where the pads can be shaved about a 1/8" on each side.