Headers? We don't need no steenking headers!

Headers are a standard replacement for many enthusiasts who look to upgrade their stock iron exhaust manifolds and increase efficiency and gas mileage. Unfortunately, Trailblazer/Envoy owners with the Inline 6 cylinder engine have been teased by more than one manufacturer that headers for the I6 were "almost there". I have been hearing this since 2004, and still nothing. So I decided to take an alternate route. Actually, I had done this same mod on my old blue Trailblazer but had no pictures. I at least took some pictures this time.

Step 1 - Start with buying a brand new exhaust manifold from GM. Be careful of the year as there was a slight change at some point. For my 2006 it is part# 12587310.

Step 2 - Ship the shiny new manifold to Extrude Hone for their AFM (Abrasive Flow Machining) process.

You can tell what the inside surface of the manifold used to be like by looking at the 3rd picture. In the center, behind the ridge there is a flat surface where the powerflow did not touch. Compare that rough surface to the absolute smoothness of everywhere else.

Step 3 - After receiving the part back from Extrude Hone, get it ceramic coated for corrosion protection and to keep the heat down in the engine bay. I have a (fairly) local shop I have used before - Fireball Coatings - they do great work. Since it ends up behind the heat shield anyways, there is no point going the polished silver look (which is not as good a heat diminisher as the black). Sorry, no pictures.

Step 4 - Enjoy.

This time I was much luckier. As the vehicle was newer, there was no problem of the bolts breaking off (as unfortunately, The Roadie's did). Money-wise, I know its more than even ceramic coated headers would probably be, but I am not holding my breath on headers coming out any time soon.