2004 Pontiac GTO Long-Tube Header Installation - Easy Breather

Using a pair of tinsnips, notch the gaskets so that they slide over the header bolts when installed. This will help immensely when trying to set the gaskets for the headers.

Set in the passenger-side header from the top. Then start the two outside bolts, and drop the gasket in between the header flange and the head. Install and tighten the rest of the bolts as much as possible. There's no point in torquing them to spec yet: You'll tighten them again after the engine has been heat-cycled a few times.

Take off the 13mm retaining nut that holds the steering shaft onto the rack, and gently disconnect the steering shaft from it. We put vise grips on the rack side to keep it from moving.

Unbolt the two 17mm cradle-to-rack fasteners that you scribed to the cradle.

Using a 3/4-inch open-end wrench, or better yet, a line wrench, disconnect the power-steering fluid lines from the rack. Take extra care not to lose the O-rings that seal each line. These can be tough to find if you drop them and will cause a leak if reinstalled incorrectly.

Lower the rack and let it hang. This won't cause any damage if done gently; don't let the steering input shaft move.

Now, remove the four 13mm nuts that retain the brace, shown here.

Reinstall the two nuts on the driver-side frame as far down as they will go, and use an air grinder to cut off the excess threads protruding from the nuts. This allows extra clearance for the header when the engine moves during acceleration.

Carefully install the driver-side header from the bottom. It's impossible to see everything from a single view. This is a two-person job: one to guide the header and one to lift it into position. Once seated, screw in all of the header bolts and snug them topside.

Using some anti-seize, install both O2 sensors in the header collectors; plug in your O2-sensor extensions as well.

Using a hacksaw or power saw (trust us, you'll want to use the power saw), notch the new catalytic-converter entry-and-exit pipes to help them seal better. Before cutting, insert a rag into the side of the catalytic converter to keep metal shavings out of the unit, which could cause it to fail.

Loosely install all the provided clamps in their respective locations, and slide on the catalytic converters and rear pipes. After this is accomplished, bolt the converters to the factory adjustable mounts.

Reinstall the factory after-cat and gaskets if necessary, and tighten all the clamps once the exhaust is positioned correctly. However, we'll prototype a '04-'05 rear bumper-conversion exhaust at Stainless Works in our next installment; then we'll put our Goat on the dyno to find out how much power it picked up at the tires!