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1998-2002 GM F-Body BBK Full Exhaust Headers Swap

Repairing and upgrading any muscle car may conceal many surprises since you don’t always know what’s in a car till after you take it apart.  We are going to swap out an old rusty set of exhaust headers on a ‘99 TransAm to help the LS engine breathe better.  Lots of changes have been introduced since 15 years ago.  The newly designed, larger diameter, Y pipe configuration BBK Exhaust Headers will definitely allow some more ponies out of the barn when we are done.

The new exhaust headers are full-length and come equipped with a ceramic coating to keep the exhaust headers system from rusting and to better control heat radiated from under the car. There are no cats on this system so we will not be legal by emission standards in some states.

Click here to hear how great they sound. The BBK Exhaust Headers are $525.00 from 1 Shopauto’s arsenal of go-fast goodies:

Exhaust Headers for LS1 F Body

Let’s review what it took to swap the new exhaust headers, and what power was gained.

 

This is what the new full length BBK ceramic-coated exhaust headers look like:

New BBK Full Headers New BBK Full Headers

First we’ll remove the old equipment and prepare the surfaces:

Disconnect the Battery Cables Disconnect the Battery Cables
[1] To start, disconnect the battery and begin dismantling the old EGR system. This original emissions system was eliminated years ago, but the tubing and hardware remain and will only get in the way of everything we try to do—such as changing plugs.

Disconnect Lines / Plugs Disconnect Lines / Plugs
[2] Remove the fuel line from the rail to gain access to the coil packs. Then remove the plugs and plug wires, then unplug and unbolt the coil bracket and set them aside. Quick tip:  be sure to take pictures so that you can quickly identify how to re-assemble these lines and brackets.

Remove Flange Bolts Remove Flange Bolts
[3] Free from clutter, he then removed the four center bolts from each header flange and loosened the outermost bolts, leaving them on to hold up the headers.

Cut Intermediate Pipes Cut Intermediate Pipes
[4] Cut and remove the intermediate pipes after the header flange and prepare to remove all old rusted components to make way for the new exhaust.

Flange Loosening Flange Loosening
[5] The old header’s flange made disconnecting the headers very easy. That said, be sure to spray the bolts with liquid wrench or a similar product to help dis-assemble the rusted parts. Go slow when you unbolt old hardware to keep from cross threading the bolts and if you are using a pneumatic wrench just break the nuts loose and re-shoot them with liquid wrench to ease the rust out of the threads. Otherwise you may have to break out the saws-all to cut each stripped bolt.

Remove Heat Shield Remove Heat Shield
[6] If you need more room for the exhaust, use a jack to elevate the old K-member slightly to remove the old heat shields that are above the headers along the body.

Old vs New Header Old vs New Header
[7] The designs of the two headers are notably different. The longer 171⁄2 to 281⁄2-inch primary tubes of the long-tube header should make more power and torque. Both headers feature a primary size of 1.75 inches and a collector size of 3.00 inches (the Y-pipe is 2.50 inches).

New Flange New Flange
[8] Thick 3⁄8-inch flanges are standard and the internal welds are smooth, too.

Rusted-out Headers Rusted-out Headers
[9] Old rusted headers become weak and lose their structural integrity. This means low performance and weak sound.

Header Gasket Set Header Gasket Set
[10] BBK supplies its own quality gaskets to replace the old worn-out gaskets.

Apply Sealer Apply Sealer
[11] Be sure to clean the head surface off lightly and then apply a thin layer of high-temperature Ultra Copper gasket sealer to ensure no exhaust leaks.

Putting the Headers in Place Putting the Headers in Place
[12] The headers slide into place from the bottom of the car and we torqued the bolts to 18 ft-lb. The ceramic coating makes them look great and provides a visual improvement over the rusty pieces they replaced. The spark plugs were reinstalled and torqued to 11 ft-lb.

Quick trick: The headers were very tight along the heat shields, so with the motor mounts loosened, Robert used a pole jack and raised them up until they creased the heat shield, thereby providing more clearance. This will prevent any annoying rattles or banging of the floor pan—a trait synonymous with F-bodies with long-tube headers.

We didn’t need to extend our O2 wires to install our headers, but some cars may need it. If yours does, BBK includes the wiring you’ll need to make your extensions.  We treated the head exhaust studs with a coating of anti-seize before installing the pipes and fasteners.

Headers In Place Headers In Place
[13] After cleaning the end of the I-pipe an impact pipe expander tool will open the mouth of the inlet. Test-fit everything before tightening and confirm the correct way to install the Y-pipe. You may need to remove the transmission exhaust hanger and then reinstall it once the pipes are in their correct location.

Weld to the Muffler Weld to the Muffler
[14] Position the muffler and exhaust tips, then tighten the nuts around the collectors and the connection for the crossover.

[15] Next you need to weld the muffler and Y-pipe back together.

 

[16] The final step is to re-assemble the fuel lines, plugs, wires and brackets that you dis-assembled in step 2 above.

You can see what great changes the new headers made both with a crisper sound and more power than the old ones.

Click here to hear how great they sound.

Spectacular Results! The engine’s HP rocketed from 348.65 to 364.10 and max torque climbed from 353.90 to 372.80. That means we picked up 15.45 hp and 18.90 lb-ft of torque at the rear wheels over baseline pulls with a basic quality $500 set of headers. Of similar importance, it made over 35 lb-ft of torque below 3,500 r.p.m.

Dyno Test Results Dyno Test Results

Article Credit from High Performance Pontiac :Hot Rod Magazine.

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