I have an 04 Z71 with the 5.3L. Wanting to install headers, and exhaust.

Question

Most headers say something about EGR. Do I have that and will it effect HP or fuel efficiency if the headers dont support it?

Answer 1

You need to install the headers that are made for your year! The emission stuff needs to be in working order for it to pass emissions! The egr actully helps an engine, it reduces compustion temp.!

I have an '02 K1500, 5.3 and put on headers and didn't notice much of a change in perf., the factory exhaust manifolds are pretty much of a header design made out of cast iron already! I put on powder coat type, which have a lifetime warranty, but for the money I spent on that, I wish I would have spent it towards a Borla system or a GM performance system. Try WWW,GMPERFORMANCEPARTS.COM. They sell their overstocks there, you can get a system cheap and usually will fit better on the truck!