Header, Chevrolet Colorado 5-cylinder, Shorty Style (see 4-cylinder Colorado headers)
Bolts in with no modifications, except the requirement to extend the wiring to the oxygen sensor, and add oxygen sensor bung on trucks with 3.7 engine. Not emissions legal. Fits 2wd and 4x4.
The original metal exhaust manifold gasket can be used.
The seal (GM part # 15105884) between the headpipe and exhaust manifold can also be reused, if care is taken to remove it from the stock exhaust manifold.
The header requires lengthening the wires to the forward Oxygen sensor on 2004-2006 trucks with the 3.5 engine.
On the 2007 and newer trucks (with the 3.7 engine), the header requires lengthening wires to both Oxygen sensors, and welding the bung for the second Oxygen sensor behind the second catalytic converter. At this time, we don't know if this will prevent the check engine light from coming on.