If it was me, I would. When I powdercoat, I never do the flanges.

They shouldn't have pc'd the flanges, should have been masked off with high heat tape after washing and prior to spraying.

There is no ceramic powdercoat, Ceramic coating is a paint, and sprayed with a paint gun, You do not need to sand the flanges. You will be fine, thats how all the ceramic coating places do it, inside and out on on the flanges.

I went through a similar situation when I had my manifold thermal coated inside and out at a prominent powder/ceramic coating shop and it's normal if you do inside and out. It's impossible to leave the flanges untouched although it looks like you have a FP race manifold and you'll probably do better dissipating heat by getting a JM Fabrication heat shield over ceramic coating.

Leave it it wont hurt you may do more dmage to the flange surface

If you do decicde to sand it off there is a Vfaq on this site that describes a good way to do it. I think it is titled "truing exhaust flanges". I don't think the coating will affect sealing, you may even benefit from the extra "squish" but that is just my opinion.

If you use some copper gasket spray on both gaskets, it should seal any small surface imperfections there may be (if any).

Ahsieh2 said:

If you do decicde to sand it off there is a Vfaq on this site that describes a good way to do it. I think it is titled "truing exhaust flanges".

Click to expand...

I am going to go ahead and sand off the coating on the flange, and my finishing method that I had in mind was the same as the VFAQ that you mentioned. Thanks for all the input!

BTW, I have included the link to that for anyone interested.

http://www.dsmtuners.com/forums/articles-intake-exhaust/311991-true-your-exhaust-flanges.html

If it was me I would sand it off...