What can I add to my 01 V8 Silverado 1500 to go faster

Cold air intake, a chip and 3" dual exhaust are the easiest and cheapest way for bolt on horsepower.

I already have a cold air intake in it that's what the vortec is and I have a flow master 10 on it

No the Vortec is what GM calls their truck engines. A cold air intake is an aftermarket bolt on pipe(usually its metal) and air filter that takes the place of the factory air filter box, air filter and black plastic tube that goes to the intake. Full dual exhaust is much more horsepower than just a muffler. The computer chip will add a lot of horsepower as well.

What's the best chip...plus the truck has 167000