Eta?

Doublexl, those raised areas are there for a reason. You should not have removed them. They are supposed to be there to ensure a perfect seal with the stock gasket. This raised weld creates a pinch point around the cylinder and eliminates the chances of flange warping causing a leak problem. This is not an issue of quality at all. This is outside the port and has no effect on power or function (clearly based on our results) other than to ensure a good seal. There is no need to supply new gaskets for the head because the OEM are metal and re usable almost indefinitely.

Our power gains and testing speaks for itself, there is no issue of quality just your opinion.

You should have contacted us directly if you had an issue. We stand behind our stuff 100% and if for any reason you were not happy before install we would have gladly taken them back. Now it is obviously too late for that since you have modified them.

mating surfaces should be flat. now that i have one finished i can comment on the poor weld quality. no back welding and a ton of undercutting on what is supposed to be a flat surface for a good sealed connection. also there should be a clean connection between tube and flange. i did the best i could short of re-welding the insides then grinding them smooth.

which would you rather install. this



or this



i know which one has a lower risk of pinching a gasket due to uneven surface....

here is before



here is after



and like i said, the undercutting and tool marks from previous are too deep to "safely" remove... i already have 8 hours into this one side. and they are definitely straighter and more even then before i took my hands to them.

Hello Doublexl -

Dude, I'm afraid you're wrong on this.

Grinding off those cups simply isn't something you should try to do by hand and by eyeballing it. Thousandths of an inch make a difference... In addition, the amount of surface area that now must have a complete seal is significantly increased. With heating and cooling cycles, I think you'll have an issue with seals as a result...

Those cups provide a way to leverage the flange such that the seal is at each port...not along the entire length of the assembly.

At any rate - good luck with the project. Mine will be installed on Monday as received from the manufacturer!

Regards,
Mike

if the raised welds were perfectly round and to the exact size of the gasket, i could consider taking your word for it. but the fact of the matter is that in some places on the flanges, the welds are 1/4" wide, and in a lot of places, they are 1/8" wide and some places even less than that. so the gaskets would have to basically be perfectly placed around the header to get a good but still uneven seal.

by making a flat and level surface, it ensures a more uniform seal on the gasket around the exhaust port. therefore more evenly distributing the exhaust gas pressure on the entire ring. furthermore, by smoothing out the hard edges of the weld going into the tubes, allows for better airflow. if i owned a flowbench, i would test it out, but rounded edges are better then sharp edges any day.

i know for a fact that the flanges of the joe z exhaust on my car are perfectly flat, and have the same type of gasket you provide for connection to the exhaust system.... which are full flanged sized gaskets, meant to seal the entire surface area not a tiny 1/8" wide rim around the inside.

back to the header, since there will be no metal to metal contact, due to the thickness of a gasket being in between. my flat and even surface would seal with the exact same force as your raised welds, given that the gasket itself looks to be around 1/4 - 3/8" wide around the exhaust ports. again, with the varying width of the raised welds, some parts would utilize 1/8" width of the gasket and even less in some places, that is a pinched gasket.

and as for my "eyeballing" of straightness. before and after comparisons, as well as numerous checks during the hand filing, using multiple straight edges and a machined flat piece of metal on a table saw would confirm that the header now is closer to flat then it was with the raised welds. also, the files themselves are perfectly flat, or else what use would they be. i have 8 hours into working on this one side, as little metal as possible was taken off. each port is perfectly flat around the diameter of its opening.

now i'm done ranting, im not going to argue anymore, because i know that i just made a good product, better, and probably more reliable.

just for fun, use the internet, and search for header flanges, 99% of them have flat faces, with no raised points for "sealing" the gasket. case closed.