can any one help me im looking to get some more performance out of my 03 z71 ive done a few thing i have cold air intake throttle body spacer and flowmaster 40 and a tune im looking to spend about 500 to 1000 on mods help please

 

There has been recent discussion around the forums about electronic fans (that range from $100ish on up to $600), as well as pulley swaps. Sadly, neither of those are things I know too much about.

I'm going to assume your truck has a 5.3 in it. You could, if it interested you, do a head swap with a 5.7. My auto-shop teacher in high school ('bout 4 years ago) did something of that nature and he got some pretty decent performance gains out of it. It is possible that I am mistaken though. Can somebody confirm or deny if this would be a plausible performance upgrade?