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Discussion Starter #1
I have Kooks LT's w/ OEM gaskets that I got from the Chevy dealer. I'm assuming they ordered by VIN so they got to right ones. First, do LS1 and LS6 have different gaskets b/c the LS6 head has D shaped exhaust port? 2nd do the OEM gaskets restrict flow in any way w/ headers? I was told this but I don't believe it to be true.
 

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i think they do... the directions that came with my lgm headers said DO NOT use ls6 gaskets, use round port ls1 gaskets. i got a new pair from a dealer, i said for an ls1 but muttered something about ls6, then i didn't really look at them to see if they were round or not. duh.


hey what do i have to do to post pictures? i took a picture of the old header gasket. the holes are oval-ish. i cut them up and used pieces as 'clips' to hold the o2 sensor wires out of the way, held in place under the bolts for the torque tube plate. i replaced that too while i was at it.

cheers
 

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Yes, LS1 gaskets are round. LS6 gaskets are D shaped. LS1 gaskets work better on aftermarket headers as the conform to the shape of the Header port and they do not interfere with the Head opening. :cheers:
 

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Header to head bolts are 2 pass. USE ANTI-SIEZE
First pass is 11 lb. Ft.
Second pass is 18 lb. Ft.
AIR pipe to exhaust manifold 15 lb. Ft.
2) Gm#12553617 air tube gkts.

hpipe to catback gaskets (2x GMPN 10276792)
12558573 gaskets GM LS1 gaskets (#12558573)
ls1howto.com
Thermo-Tec hi-temp tape
Instructions posted by Lou:

The driver side header goes in from the bottom. Remove old exhaust system back to the 2 bolt muffler flanges in front of the differential. To do this, remove the spark plugs and ground strap on the driver side and install them from the bottom.

Use only stock GM- LS1 exhaust gaskets, NOT LS6 gaskets. Install all bolts finger tight in the header flange at the head. Be very careful to not cross thread the header bolts. You can install the passenger side from the bottom or top. If you go from the bottom, you might have to pry the engine over a little to make room for one flange that gets in the way. Or you can install the passenger side from the top but you will have to remove the coil packs and valve cover to install them from the top after removing the coil pack and valve cover on that side. We have done it both ways with equal success.

Do not tighten the bolts on the flange all the way until you get the bell housing bolts started. Once they are started, then you can tighten the exhaust flange on the engine.

If you have the hand made version, you should install the off road pipes or Cats with the V flange now. Some times we put a small amount of “Ultra Copper Silicon” on the V flange at the end of the collectors to insure that no air leaks into the header.
If you have the LG Pro Long Tube headers, install the slip fit X pipe using 2 of the supplied clamps. The clamp bolts should face outward at the front of the X pipe, and inward at the rear of the x pipe. >>> A leak here will confuse the O2 sensor and make the car run rich. <<<

Then continue to install the remainder of the system back to the mufflers. Keep the threaded parts of the clamps up out of harms way when they are tight for ground clearance.
After the engine is run, all bolts and clamps should be re tightened. Or we sometimes tap the pipes to vibrate the system to get the clamps totally tight.
O2 sensors:
This is very important. When you remove your old headers, you will remove all four 02 sensors. Set the old front sensors aside and do not use them, the wires are too short
Install the 02 simulators and plug them into the car harness, where the rear 02 sensors were attached to the wiring harness. The car harness has a square plug and so does the 02 simulator.
Next, take the original REAR 02 Sensors, and plug the LGM adapter into them. That will give you a long wire, with the LGM adapter which will allow this 02 sensor to be used as your main front 02sensor. Install the long 02 sensors in the collectors of the new LG headers, and make sure to route them away from any hot tubes. You must install the 02 wires one side at a time to not mix them up. The sensor on the right header (collector) gets plugged into the right side (Passenger side) and the one on the left collector gets routed to the left side plug in the car harness.
It is important that the 02 sensors go to the correct side of the car. If the 02 sensors are not hooked up correctly, the car will not idle correctly. This should be the first thing you check if a problem arises after the install. Just hook the driver’s side 02 to the driver’s side wiring harness, and do the same on the passenger side. Our 02 sensors angle across and can easily be confused. We drill a 1” hole in the upper heat shield to help route the wires, but this is not mandatory. But extra care must be taken to avoid the hot pipes so not to melt the wires.

As to your problems, you need the driver’s side back 02 sensor (with the adapter attached) plugged into the driver side front hook up. Do the same for the passenger side. The SIMs go into the plugs for the back 02 sensors on both sides. I would also pull the battery to reset the computer and then see if you get the check engine light. If you still do you need to pull the codes and define what you are getting.
Here is how and what they mean.

Please call us if you have any install questions. 972-272-7753
Hope this makes your job easier.

Also be sure to keep the 02 sims away from the headers. While they are heat resistant, too much and they will not work.

Speaking of Dipsticks...
Tip: before trying to wiggle out the dipstick, especially for a first timer, remove the dipstick from the tube first. I was pushing in and out to get that darn tube out, I didn't realize the tip of the stick hangs past the tube and bent and twisted it up like a pretzel. I tried to straighten it out
 

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IT L GO said:
Some times we put a small amount of “Ultra Copper Silicon” on the V flange at the end of the collectors to insure that no air leaks into the header.


i should have done that, it's a bitch to not have leaks.
 

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Actually, the LS1 gasket are not round. The f-body gasket are and in my opinion are better suited for a header installation. That is what QTP sends with their headers and they fit the round header port perfectly.
 

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Discussion Starter #7
So should I order OEM F-body gaskets? Any problems leaving in the Z06 ones for a it?

BUT... if the exhaust gasked doesn't block the exaust port of the head any they how could it restrict flow?
 

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Cobra4B said:
So should I order OEM F-body gaskets? Any problems leaving in the Z06 ones for a it?

BUT... if the exhaust gasked doesn't block the exaust port of the head any they how could it restrict flow?
I've got the Kooks headers and used new LS6 gaskets. Head ports are "D" shaped anyway.

I haven't had any problems, put over 1K miles so far.

augydog :thumb:
 

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Brian,
I would make sure you know if the gasket you get has the cutout for the little air hose that bolts to the header. I found out last year that at least one set of GM gaskets (LS1 maybe?) doesn't have gasket material to cover the port this hose bolts to on the stock header - big leak. Had to hunt down some correct Z06 gaskets.

This hose may hook up differently to headers. Not sure about that.
 

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vettenuts said:
Actually, the LS1 gasket are not round. The f-body gasket are and in my opinion are better suited for a header installation. That is what QTP sends with their headers and they fit the round header port perfectly.
I believe we are talking about the same thing
GM LS1 gaskets (#12558573)
:cheers:
 

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Cobra4B said:
So should I order OEM F-body gaskets? Any problems leaving in the Z06 ones for a it?

BUT... if the exhaust gasket doesn't block the exhaust port of the head any they how could it restrict flow?
The shape of the Gasket follows the contour of the header better. :z:
 
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