Anybody running 17" Cobra Bullit rims on a Duster

Something doesn't add up. Almost sounds like you have a C-Body rear axle, not a B-Body. 61" drum to drum is way wide for a B-Body. Your clearance adds up for me, but only if you moved your springs in 1/2", but then the overall doesn't add up. If you moved the springs out 1/2", it makes more sense. Either way, your housing flange to flange number makes sense for a 68-70 B-Body. Things just don't add up.

BTW, the axle that makes this work all the way around is a 65-67 B-Body at 59.5". The 68-70 is 5/8" wider at 60.125".

If your axles are out, take a really accurate measument from end of splines to outside of axle flange.

My information shows:
B-Body - 65-67, 28.875", 68-70, 29.1875"
C-Body - 65-69, 30"

Might be an E-Body too, that axle should be 29.96875".

My math shows that on a typical 65-67 B-Body axle (at 59.5" drum to drum) should have about 1" clear to the springs, but I might be missing something. This is based on a 43" c-to-c spring and 2.5" spring width, and a 245/45R17 tire on a 17x8 rim with +30mm offset. 245/2 + 30 converted to inches shows about 6" from mounting surface to inside of tire. 59.5 - 6 - 6 - 43 -2.5 = 2", divided in half shows 1" clear on the inside.

Not arguing with you James, but a 69 B-Body rear axle would have been even wider than that. Don't know what you had, and maybe I am missing something, though.