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What is considered a warped header flange?

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Old May 2, 2019 | 09:40 AM
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Default What is considered a warped header flange?

At what point do you have sealing issues?

I'm asking because I have a set of TSP 1 7/8" Longtubes and when I went to bolt them up the drivers side was fine, the passengers side was pretty concave. It appears that the "ears" on the outer edges of the flange were bent. So I took them to a local machine shop, they threw it up on the big belt sander and started to work on them. The guy said they got it to where there was about .006-.007" gap right around the 3rd tube which he said he felt should seal up fine with a good MLS gasket, and that he didn't want to go grinding on it any more because he didn't want to cause any fitment issues.

So my question is, what do you guys think? Sound reasonable?

I've searched and found a thread that Kooks responded to a while back where they said uneven flanges are normal and that it'll seal up fine. The owner of that set quoted measuring .040" concave. I'm not sure if they sealed up for him or not as he didn't update the thread.

Just looking for some opinions here.

Thanks
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Old May 2, 2019 | 10:33 AM
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My brand new Kooks header flanges were very concave out of the box (at least 1/8"). It didn't bother me on bit, though, because the bolts pulled it flat against the head perfectly with very little force, meaning they pulled flat to the head way before final torque was reached. It's been two years and there has not been one leak yet. Before grinding them, did you try bolting them to the head to see if they would straighten out?

I would bolt them to your head right now without gaskets just to see if they pull flat against the head. Check it in a variety of places with feeler gauges. If they pull flat to the head, put a gasket in and you're good to go.
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Old May 2, 2019 | 01:21 PM
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When you see daylight thru a straight edge layed on it?!
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Old May 3, 2019 | 10:18 AM
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Originally Posted by 98RedBird
The guy said they got it to where there was about .006-.007" gap right around the 3rd tube which he said he felt
If true, you are good to go
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Old Sep 16, 2019 | 06:41 AM
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Any warp is "not good" but its pretty common, especially after some miles and heat cycles.
You did good getting a light resurface in them.

Have all your tools ready. Bolt them up loosely with a good gasket and high temp rtv on both sides of the gasket, tighten from the center out to torque spec before rhe rtv sets up, go drive or get them up to temp and retorque to spec while hot. Buy good new bolts, use real antisieze on the bolts, not grease. Common practice from old race days reusing well worn beat up headers.
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Old Sep 27, 2019 | 09:39 AM
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You might want to consider Remflex gaskets. They crush when installed and can fill a small gap.
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