Thread: SD Rear header sealing problem...

I sanded the flanges with a 6" belt sander to remove most of the clear paint, and straighten them slightly, I also re-used the oem gm header gasket.

The egr connection I put a good bead of copper rtv in when the egr was slid together, then clamped the egr tube to the header, let the car sit for at least 2-4 hours to keep the rtv from this joint from entering the supercharger. (I put copper rtv on all joints except the main ports to the header)

I had the flex flipped (v-band is now at the top of the flex/ bottom of the rear header) so it can be repaired without removing the rear header.
I also had a second o2 bung welded on the drivers side of the rear header as far forward as possible opposite the supplied o2 bung. (was going to try using this for wideband, but it has 3/8" clearance and the stock one has no clearance for the o2 sensor, need to fix this first.)

Check to make sure all header bolts are tight. I bolted the rear header in tight first, I believe it would have been more troublesome to tighten up if it were all assembled loose, then the bolts all tightened.

Unless you're building a race car and need to reduce weight, don't bother to delete the EGR. They're nice and DD's love them. Besides which, the EGR valve is 100% CLOSED at idle. You could unbolt it from the headers and it won't make a difference at idle. EGR only opens at cruise.

It's also got nothing at all, ever, for any remote reason, to do with your flex if you're feeling the exhaust leak at the manifold.

Make sure all of your header bolts are actually tight and that your gasket is seated properly (it sounds stupid, but I've seen the gasket on wrong before). Some guys even use lock washers on the bolts for some extra oomf. There should be nothing wrong with a new GM gasket, but Felpro header gaskets are a bit thicker so are more likely to seal nice and seem to be more popular than GM gaskets for that reason.

After doing my SD headers, my POS EGR leaked like a b*tch. I proceeded to unbolt it, and throw it as high into the air as I could. Block off plate on te header EGR port, an no more ticking!