We have pulled a medium size (26' 4600lb UVW) trailer with a 99' Tahoe with a 5.7/3.73, a 2006 Tahoe with a 5.6/3.73, and a 2003, 2500 Suburban with the 6.0 and 4.10 rears. IMHO, a 1500 Suburban, from that era, is going to leave you one unhappy camper once you head into the 6000+UVW range. The best you will probably find is a 5.3/3.73 combo. and it will be very marginal, at best. The other thing we found is that there are a hundred 1500 Suburbans available on the used market, for every 2500 out there. When we narrowed it to a condition and price range, I found four within a few hundred miles of us. Good luck.
