For the rear on the FRONT you could use the stock cast spring hangers or go with an FUSH kit from offroad design. Same thing but their kit uses larger bushings and you have to use their shackles. I ended up just buying new bushings and making my own shackles for that part.
There is no direct science for figuring out where they go aside from a lot of measuring and comparing frames. I will go back and remeasure to get the correct spacing for future reference in case someone doesn't have a spare frame to measure from, but what i ended up doing was measuring from the backside of the front mount, to the front of the rear mount. Then using a hole saw to cut out the center bushing part and then bolted the bracket in to place. I will note that on the 4x4 frame the rails sweep up just ahead of these brackets and allows the spring and shackle more travel room and its mounted higher up in the frame rail on 4x4. I ended up buying shims to correct my pinion angle which I have not installed yet.
front axle pulled from the donor chassis
The old stuff comes out as a unit thankfully.
front axle jacked in to place with the stock 4x4 springs
simple shackles I made. Not finished in this pic obviously
