If your 8 3/4 axles are 35 spline then they can be made to work, I just went through that last fall I shorten the Ford 3/4 ton P.U. Dana 60 one inch narrower than the 8 3/4, 1/2 inch per side. I had to wack about 3/8 inch off the right side axle to make it fit without touching the left axle in the spool, I did have the Dana 60 axle shorten so the Dana 60 pinion ended up in the exact same location as the 8 3/4 pinion center was I also bought the Moser axle ends so I could use a stock inner axle seal to keep the rear end grease from leaking out of the axles onto the brake backing plates and onto the brakes. The green bearing O rings and stock foam axle gaskets would leak and seep some