After having some problems with finding gaskets to seal the Sikky headers I bought a set of new Hooker Headers for LS1 swapped 240sx. They have flat flanges so they will seal against pretty much any gasket. If it is one thing I hate it is exhaust leaks. With that said I decided to go with a slip fit and flanged connection on the ends of each header.
I first took some 3/8 thick 3 bolt flanges and bolted them together. I chucked them in my lathe and machined one flange to accept the outside diameter of a slip fit tube.
I then bolted it all together and welded the flanges on. You can see how the flange is welded a couple inches up the collector. I will still be running gaskets as well. This setup will keep the exhaust from directly contacting the gasket as well as giving very little chance of the exhaust even getting to the gasket to leak.
The only flanges I could find were stainless steel. I welded them all on my TIG using 309L stainless rod. The slip fit collectors did have to be ported out after welding.
Here are the set finished up. I’ll be mounting the catalysts about a foot or two back from them.