Hey folks, I posted this in the wrong place the first time so im gonna retry, I have a 96 k1500 5.7 3.73 gears with an auto 265/75/16 tires, my gas mileage is about 12ish, which seems low being dads 97 Tahoe gets 17ish, I think its because my truck seems weak and in a strain. That being said what's the best upgrades I can do? Would headers and a custom tune get me any were near 300hp? Currently running 2.5 inch true dual flowmaster exhaust, k&n and modifyed throttle body, recent tune up, plugs, plug wires, cap and button and distributor, coil and also a new fuel pump and upgraded fuel spiders...... I think that's bhout it. Lol, any help would be appreciated...

 

Cold air intake is missing from your list..

 

A cold air intake make much diff over the k&n with out the top on the air box? If so is one cold air intake better than any other? Thanks