OK, so I took a quick trip to O'Reilly Auto Parts, I had them pull the rotor for a 73 C-10 (
5006RGS Link) I also had them check the part number for a 91 2WD Suburban to which they are the same. The outer dimension (center of wheel opening) where the wheel will mount is 3". I had them pull a hub for a 2WD 2013 Silverado (
Precision Hub Assembly Link), the outer dimension (center of wheel opening) was 3". That solves that problem. Now my only concern is the wheel mount to wheel mount dimensions matching up.
notsolo - I have found that (supposedly) the 88-91 Suburbans use the same cradle as the 73-87 trucks. I will get this verified before buying.