If he has a V6 in there, there was a head gasket recall for it; have him read up at the thread below:

Head Gasket Recall Information

He can take the VIN to the dealer and see if has been taken care of if you guys aren't the original owners of the truck.

The 3.4 swap is popular; take a look around here for the thread; fellow did a nice writeup, and it's going to become a permanent article on this website.

If it's the 4 banger and he wants more power, he needs to talk to some of the EB'd 22R owners here, otherwise he's going to shell out some bucks for a new drivetrain to handle 'more power' for the torque.

If you guys are on a budget, a rebuild will give you back some power and gas mileage. Also have the fuel injectors sent off and cleaned/refurbished:

<a href="http:/www.cruzinperformance.com" target="_blank">CruzinPerformance</a> People have done business with these guys and are pleased.

Hope that helps getcha started anyway; welcome to the board!