K20 Rotor size issue

[polishspy]

Ok, I am confused on this one.

I have a 1970 K20 suburban and i have swapped the front axle to get disc brakes from an 85' K20. I have rebuilt the locking hubs (new locker, bearings, the works) and went to go put on new rotors (Bendix prt1049) which say they fit but, I have a clearance issue with getting them over the outer flange of the locking hub. Am i missing something, i measured the rotor inner diameter and it is just shy of 8 inches, but measuring the outer flange of the locking hub im close to 8 5/16 in. Any ideas on what rotor I would need?