Installation Manual

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GP129S-C

CERAMIC HEADER

NO AIR INJECTION, NO EGR

CADILLAC ESCALADE 6.2L AWD

CADILLAC ESCALADE 5.3L AWD

CHEVY AVALANCHE 5.3L 2/4WD

SILVERADO / SIERRA TRUCK 1500 4.8L-5.3L 2/4WD

SILVERADO TRUCK 1500 6.0L VORTEC MAX 2WD

SUBURBAN / TAHOE / YUKON 4.8L-5.3L 2/4WD

CHEVY SUBURBAN 2500 6.0L 2/4WD

YUKON DENALI 6.2L AWD

GMC SIERRA DENALI 1500 6.2L 2WD

HUMMER 6.0L

HUMMER 6.2L

GIBSON HEADERS ARE 50 STATE SMOG LEGAL

Thank you very much for purchasing our Gibson header for your vehicle.

If you need further assistance, please do not hesitate to call our Technical Department at

(800) 528-3044

Monday through Friday

8:00 a.m. to 5:00 p.m. PST.

1270 WEBB CIRCLE CORONA, CA 92879

Summary of content (7 pages)

PAGE 1
GP129S-C CERAMIC HEADER NO AIR INJECTION, NO EGR CADILLAC ESCALADE 6.2L AWD CADILLAC ESCALADE 5.3L AWD CHEVY AVALANCHE 5.3L 2/4WD SILVERADO / SIERRA TRUCK 1500 4.8L-5.3L 2/4WD SILVERADO TRUCK 1500 6.0L VORTEC MAX 2WD SUBURBAN / TAHOE / YUKON 4.8L-5.3L 2/4WD CHEVY SUBURBAN 2500 6.0L 2/4WD YUKON DENALI 6.2L AWD GMC SIERRA DENALI 1500 6.2L 2WD HUMMER 6.0L HUMMER 6.2L GIBSON HEADERS ARE 50 STATE SMOG LEGAL Thank you very much for purchasing our Gibson header for your vehicle.
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WHEN THESE INSTRUCTIONS ARE FOLLOWED PRECISELY, YOU WILL FIND THE INSTALLATION OF YOUR EXHAUST SYSTEM TO BE RELITIVELY SIMPLE. WE CANNOT OVER EMPHASIZE THE IMPORTANCE OF ADHERING STRICTLY TO THIS PROVEN APPROACH, AS IT WILL VIRTUALLY ELIMINATE ANY DIFFICULTIES, WHICH YOU MIGHT OTHERWISE ENCOUNTER.
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SUGGESTED TOOLS 13mm, 12mm” WRENCHES (VARIOUS LENGTHS) 12mm, 13mm” SOCKETS (SHALLOW AND DEEP) 9/16” WRENCHES (VARIOUS LENGTHS) 9/16” SOCKETS (SHALLOW AND DEEP) 5/8” SPARK PLUG SOCKET 15MM DEEP SOCKET 15MM BOX END WRENCH 3”, 6”, AND 12” EXTENSIONS FOR SOCKETS HIGH TEMP SILICONE (ULTRA COPPER BY PERMATEX) GOOD RUST PENETRANT
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INSTALLATION INSTRUCTIONS FOR GIBSON SHORTY HEADERS GP129 INSTALLATION OF THESE HEADERS REQUIRES AN ADEQUATE WORKSPACE, GENERAL MECHANIC’S TOOLS, GENERAL MECHANIC’S KNOWLEDGE, AND A REASONABLE DEGREE OF EXPERIENCE. MOST AUTO-ENTHUSIASTS WITH THESE RESOURCES WILL HAVE LITTLE DIFFICULTY INSTALLING THESE HEADERS. HOWEVER, YOU SHOULD CAREFULLY READ THE INSTRUCTIONS BEFORE ATTEMPTING TO INSTALL THESE HEADERS. IF IN DOUBT, CONSULT A PROFESSIONAL MECHANIC.
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6) RE-INSTALL THE SPARK PLUG WIRES AND RECONNECT THE STEERING SHAFT ON THE ALIGNMENT MARK. 7) ON THE PASSENGER SIDE REMOVE SPARK PLUG WIRES AND SPARK PLUGS AND SET ASIDE. REMOVE THE BOLT ATTACHING THE DIPSTICK TUBE BRACKET TO THE HEAD. THEN REMOVE THE DIPSTICK. DO NOT LOSE THE DIPSTICK BOLT YOU WILL NEED TO RE-USE IT. 8) REMOVE THE SIX BOLTS ATTACHING THE MANIFOLD TO THE HEAD. REMOVE THE MANIFOLD.CLEAN THE SURFACE OF THE HEAD. REMOVE ANY CARBON DEPOSITS THAT MAY BE ON THE HEAD.
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10) RE-INSTALL THE DIPSTICK TUBE. WRAP SPARK PLUG BOOT WITH HEAT WRAP PROVIDED AND RE-INSTALL. USING THE NUTS AND BOLTS PROVIDED, RECONNECT THE HEADERS TO THE STOCK EXHAUST UNDERNEATH THE VEHICLE. NOTE: On some models, may need to bend heat shield out of the way on passenger side header. Due to header tube being very close to heat shield. (Only some models.) 11) FINALLY, MAKE SURE ALL BOLTS ARE TIGHT AND EVERYTHING IS RE-CONNECTED. START THE ENGINE AND LET IT WARM UP. CHECK FOR LEAKS.
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IT IS CRITICAL THAT ALL BOLTS BE RE-TIGHTENED HOT AFTER ABOUT 20 MINUTES OF OPERATION TO PREVENT GASKET FAILURE. NOTE: HEADERS ARE NOT MEANT TO SERVE AS “EXHAUST SYSTEM SUPPORT HANGERS”. ADDITIONAL HANGERS MAY NEED TO BE ADDED AT THE TIME OF THE INSTALLATION OF THE HEADERS SO THAT THE EXHAUST SYSTEM SUPPORTS ITSELF WHEN THE COLLECTOR BOKTS ARE REMOVED. HEADERS THAT HAVE “SAGGED” DUE TO THE LACK OF SUFFICIENT EXHAUST SYSTEM SUPPORT WILL NOT BE REPLACED UNDER WARRANTY.