I've got the same boat as you, except an 88. I tow with a 2004 Chevy Silverado 4.8 extended cab. We've towed the boat about 150 miles, two adults, two kids, boat toys, camping gear, food and ice for a week with no issues. I'd guess easily 700-800 lbs of stuff in the truck, a full tank of gas in the boat. No idea what mileage was, I'd guess 14-15? No major problems pulling the hills, either. I occasionally wish I'd gotten the 5.3, but truth be told, the 4.8 moves me just fine. Picked it up used for $7k.