8-lug to 5-lug swap

[1972GMC2500]

I'm swapping out the old 8-lug Eaton in my 1972 GMC 2500 for a 5- lug 12 bolt from a 1971 c10. I have the old axle out and I noticed that the track bar mounts closer to the pumpkin on the 12 bolt than it did on the old axle. Are the frame side track bar mounts different on the c10 and the 2500? If so, does anyone know where I could get the c10 mount? I checked in my LMC catalog, and they don't seem to offer them, just the bolts for the end of the track bar.
I know many people have done the 8-lug to 5-lug conversion, so I know there is a solution.
Thanks,
Gregg