LGM Long Tube Headers
All of these installations are to be performed at your own risk!!!!
Opening up the exhaust on a C5 is one of the best mods you can do. This will give you a substantial increase of horsepower because the C5 engine has so much to offer but it is bottled up power waiting to come out. The OEM manifolds are very restrictive on the exhaust flow and robs a lot of horsepower.
LG Headers are self proclaimed the most powerful headers on the planet but seem to prove true in all cases that I've seen or heard of. I have never heard one bad thing about them and the dyno results are nothing short of astounding. They are mandrel bent stainless steel which are true long tube headers at a whopping 32" with 3" merge collectors and 1.75" primary tubes. These headers are proven to produce the most low end torque while maintaining peak horsepower at high rpms. They are just bad ass. This header package, with a dyno tune, gave me over 40 rwhp! You can see the dyno sheets here.
To do this install I used the excellent writeup provided by LS1 How To and tailored it my way by changing a few things around that I think make the job a little easier. Let's get started. It's time to uncork that engine and allow it to release the power it was designed to do!
Tools you will need:
Supplies:
The LGM header package will come with the following:
Step 1 (Removal of stock h-pipe):
First you must jack up the car in the rear and place on jackstands. As with all of my installs, I like to have labeled plastic cups to throw any nut, bolt, or screw in so I am able to tell where it goes during reassembly. Next, jack up the front and place jackstands or ramps under the front. For now, you just need enough clearance so you can comfortably work under the car. After the car is jacked up the first think you want to do is disconnect the h-pipe from the stock manifolds. To do this, remove the 6 15mm nuts that hold the h-pipe to the exhaust manifolds. There are 3 on each side. If they give you any trouble hit them with some Liquid Wrench or WD40.
Now, go to the rear of the vehicle and remove the 15mm bolts that hold the h-pipe to the catback (muffler system). You now have 4 remaining bolts that hold on the h-pipe. Now, go to the rear of the vehicle and remove the 15mm bolts that hold the h-pipe to the catback (muffler system). You now have 4 remaining bolts that hold on the h-pipe.
Remove the 2 13mm "spring" bolts around the center section of the h-pipe. Place jack under the "H" section of the pipe for support.
Unclip the wiring for the oxygen sensors and let it dangle freely. This will allow the h-pipe to drop down to the ground. If you are using a lift you will want to unplug the oxygen sensors before dropping the h-pipe. You can see how to do that later on in this writeup.
Now, remove the remaining two 15mm bolts that attach the h-pipe to the bellhousing. Remove the ones below my finger and not the ones I am pointing at. You want to keep the bracket in place on the bellhousing. You can give it a couple of jiggles and lower the jack supporting the h-pipe and slowly bring it to the ground. Keep an eye on the oxygen sensor wiring to make sure you have unclipped all of the clips you need to and lower it slowly as it is fairly heavy.
Disconnect the oxygen sensor plugs. There is one on each side. After doing so, slide the h-pipe from under the car and remove the oxygen sensors with a 7/8" open end wrench or a crescent wrench. You will use the sensors later for the front of the long tubes.
