On flat ground, and lower elevations, that thing will tow anything you want to hook behind it. The steeper and higher you get, the more you'll wish you had a diesel. You'll be amazed how much headers and exhaust (and cat removal if possible) will improve power. If you're willing to drop a little money into it, I'd do the Edlebrock cam and TBI intake too. As stated before, the 4.10's will help if so equipped. If it's a 3.73 rig, I'd suggest keeping the tire size at 265 or smaller if towing power is your goal. When you start towing the Blazer, I'd add an auxilary trans cooler and temp gauge for insurance.