Take Caution Before you install new headers
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Take Caution Before you install new headers 
Caution before you install new headers I would like to share my recent high dollar poorly made long tub header ordeal. I bought a set of headers and y-pipe for my Silverado. It took six weeks for the headers to show up. Now the first thing I should have done was put a strait edge on the manifold flange to check if it's flat. I didn't do this but I will from now on, at almost 9,000 miles I had to take headers off cause the pass. side was hitting the frame. I also notice the Percy gasket that came with the headers had started to leak. Sent the headers off to get fixed and the pass. Header flange was wavy and I could measure .025 warp between two ports! I went an measured drivers side and got .023 warp and they never even touched that header. GM spec for the manifold warpage is .010 all the way across. So I told them I wanted a replacement set these are not going to seal very long. They finally sent me another set but they both have pinholes in the welds on the collectors. I would strongly recommend that if you are running kooks headers you may want to get them checked out. I'm never gonna deal with them again. Attached Thumbnails
What brand are they?
I put Speed Engineering headers on my Silverado. They fit fine other than the DS header was barely touching the front diff yoke. This wouldn't be a problem on a truck with a lift that drops the front diff, but I just dimpled the primary a little.
I put Speed Engineering headers on my Silverado. They fit fine other than the DS header was barely touching the front diff yoke. This wouldn't be a problem on a truck with a lift that drops the front diff, but I just dimpled the primary a little.
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Paul Bell, I did not check the original set before I put them on but when they tried to repair the passenger side they never touched the drivers side so I measured that header as well and it was .023 warp. The second set never made it on the truck but I did measure those and both headers were warped over .020.
Paul Bell, I did not check the original set before I put them on but when they tried to repair the passenger side they never touched the drivers side so I measured that header as well and it was .023 warp. The second set never made it on the truck but I did measure those and both headers were warped over .020.
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Right now I'm still running the original set (which are leaking again) because this is my DD. The way I see it is these headers are defected and they should either replace them with a good set or refund me for manufacture defect. Twice!!
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Verdad Gallardo Yeah I agree. I bet you wont see a refund. After two sets were f'ed up they SHOULD give you a refund. In the unlikely event that they do refund you and you want the top notch stuff get the American Racing kit, otherwise save you a pile of money and get the speed engineering kit which is quite nice!
wtf is going on with Kooks there have been a number of complaints in the last year . One guy on here iirc waited close to 6 months for his then had a problem with the install. Kooks use to be a top shelf company . Something has serious gone wrong there .
Yeah, a lot of complaints on kooks products lately, never seen it like that. Something has to be going on over there...cut backs, cheap labor or just QC going to ****. I would look into american racing as well if your returning the kooks, they sell nice stuff.
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I'm not sure what's going on over there but when they screw up 2 sets of headers on the same customer that's bad. I'm not sure yet on what headers I'll go with but it defiantly won't be kooks. Anyone know if AR fits kooks y-pipe?
I've installed a couple sets of kooks headers. Honestly never been impressed with them, one hit the bellhousing on my old C6 and we dented the primary to clear the steering on my buddy's TA.
My personal preference has and will always be ARH
My personal preference has and will always be ARH
I got a set of Kooks last year. I didn't measure the flange flatness, but I did not have problems and I can't tell any leaks. Fit and finish seemed good, I got all the hardware I needed. Install went fine on my 4th gen, I had to grind a little off the K member and boss off the block but I got them in with only like 18"-20" of lift.
I have also always went against the masses and promoted ARH over Kooks. I've used both several times but ARH is nicer, hands down. This is speaking mainly for the F body stuff though. I recently did a set of speed engineering new design on my dad's car and it seems his O2' don't like them but they fit pretty good. I also have put on ebay, Texas Speed and Stainless Works. Stainless Works gets the biggest thumbs down from me on the fourthe gen F body. Now the third gen F body LS swap headers from Stainless Works are ****.
Kooks has been going downhill. It really sucks because I love their products. My headers on my Camaro have been on and off the car over the last 5+ years with no issues. I ordered the Dual exhaust and have been fighting it to fit. Took 4 months to get the exhaust and then another 2 months of calling and emailing to get any progress. I just shipped part of the exhaust back yesterday at my cost. I'm hoping to have some sort of answer in the next week or two. I won't hold my breath though.
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Chris, if the flange looked like mine chances are they are not flat. They may be pretty close though so they seal up better than what I have. If you look at the edges of the seal and notice a black or brown coloring then I would question it, just my opinion.
I had this problem with my set of Hooker stainless headers. I know from many header install that you should run a long fine tooth file that is at least the length of the entire flange because there is always some flash from chamfering the edges that could contribute to an exhaust leak.
But when I pulled the headers to swap heads this past year, I looked at my exhaust gaskets and say half a dozen leaks. They were very small and you couldn't hear leaks either. What I did was add stainless welds at every leak point and then went back with my large file and made sure all areas were equal across the whole board. Many small welds because with that amount of heat, it's very easy to warp the flange. I learned that and spent extra hours in a press to fix this. I was really only widening the machined sealing weld to fix the leaks, but the warp-gaps had me add a lot of material (half circle) to make everything equal.
Then I put a strait edge across the entire length of the flange with a light behind it and slid it across everywhere, making sure no light would show through, if it did, I added more weld and re-filed. Now they are perfect.
But I understand that they should be perfect out of the box, but I have learned that 95% of every part on my car I have had to modify or machine to get it perfect.
But when I pulled the headers to swap heads this past year, I looked at my exhaust gaskets and say half a dozen leaks. They were very small and you couldn't hear leaks either. What I did was add stainless welds at every leak point and then went back with my large file and made sure all areas were equal across the whole board. Many small welds because with that amount of heat, it's very easy to warp the flange. I learned that and spent extra hours in a press to fix this. I was really only widening the machined sealing weld to fix the leaks, but the warp-gaps had me add a lot of material (half circle) to make everything equal.
Then I put a strait edge across the entire length of the flange with a light behind it and slid it across everywhere, making sure no light would show through, if it did, I added more weld and re-filed. Now they are perfect.
But I understand that they should be perfect out of the box, but I have learned that 95% of every part on my car I have had to modify or machine to get it perfect.
Last edited by BlackDuk98; Jan 7, 2017 at 07:56 PM.
Had the same problem with my G8 with Kooks. Put them on and had a really bad exhaust leak. Took them off and layed them flat on a bench and you could see daylight through one of the ends. The flange was clearly warped. They were quick to send me a replacement header, but the replacement header had no threads in the O2 bung LOL. So I welded the bung shut and welded another bung on.