Horse power increase

I have a 1996 K1500 Z71 with a 350 vortec. I recently purchased a 5th wheel and I need alittle more horse power. I am on a budget here so I'm looking for the most cost effective way to do this. I can spend around $1000.00 including installation for this project. Any idea's or suggestions would be greatly appreciated. Thanks in advance.

You could go with a little larger cam, or a different ratio rockers. If you just want it to tow better, consider changing your rear end, which will make a hell of a difference towing but will hurt your gas milage. You could also go with an aftermarket exhaust. A lot of things can be done with $1000.