http://blog.patmcgrathchevyland.com/201 ... -capacity/"If you were to get a truck with the 4.3-liter EcoTec3 V6 engine and 2WD (with a 3.23 rear axle), then you could tow 5,900 pounds. When you swap that configuration for 4WD and a 3.42 rear axle, this number increases to an impressive 7,100 pounds despite being the least powerful of the three available engines."
Dry base weight of 4000 lbs. on the boat. As long as you don't keep the ballast full, boat loaded to the brim with stuff, etc it should pull fine, just make sure the frame is set up to be level when hooked up on flat ground. Remember that stopping is the bigger consideration. Many vehicles pull all kinds of boats fine. The stopping is where it gets to be fun.
If the frame is not level it can affect the brake actuator operation on the trailer which will affect the trailer brakes adversely. Level to 1" high at the front is the range to use. Low is your enemy!