Q: Header flange not flat

[j-rho]

So I've played around with exhaust components and headers quite a bit over the years, from the cheapest to the most expensive. Haven't seen anything like this before - this is a close-up of a section of the flange surface for some headers that just arrived. I've never seen something like this, where the flange surface is not completely flat. I don't see how this is going to seal properly? FWIW all ports appear this way. Sorry the cameraphone decided to focus on the cardboard instead of the header.



Do I send them back, grind the mating surface down flat, or try to use them like this? Was going to get them coated but don't want to spend the $$$ coating something that won't work in the end.

Thanks!!

[Motorcitydak]

Only the part that goes around the exhaust port actually needs to be flat against the head. That will crush the gasket, making the seal. I would use em like that and be careful when torquing the bolts. Be sure to torque them equally on both sides of the port. If you think about it, this way actually seems better than a completely flat flange. With that, the clamping load is spread over the entire flange. Here, it is only on the area that matters, around the ports. Correct me if I am wrong but this seems fine

[ehummelman]

Yeah, that's how my new headers on my Bronco were when they arrived from Stan's. At the price I paid, I would think that he didn't cut corners.

[j-rho]

Thanks for the feedback guys, guess I'll go ahead with a test fit. I was a little worried because the bolt holes were beside the raised section, thought maybe it would try to "bend" the header mating surface a bit when torqued.