I picked up a set of Summit Brand ceramic coated small block headers yesterday and when I got them home and out of the box I see that there's no way they'll seal up on my ported J heads. My ports are matched to the Felpro http://www.summitracing.com/parts/fel-ms90460 gaskets. The raised area around the port on the headers is too short on the bottom side of the port. The outside edge of that machined raised area on the header lands in the port on the head and well of course with no area on the head for it to match up against itll leak straight out. So my question is whose headers that Summit sells will work on my heads? Dougs maybe? But they dont say theyll fit an F-body but I would think a manual steering console shifted no torsion bar in the way 1979 Volare would have an easier time than say a 73 Dart getting them to fit. So have I screwed myself port matching to that gasket or is there a header thatll work? I saw in the Flowtech header reviews on Summits website Im not the first guy to run into this trouble apparently. The single review they had was leaking out the bottom of the port with no way to fix it.

We have run into the "port match/ seal" problem with several different brands of headers / motors even on non ported heads . Hedman seem to be the worst

making our own has been the solution,

http://www.amazon.com/Mr-Gasket-5961-Exhaust-Material/dp/B000BWAPH0

Yah Im not using these Summit brand headers thats for sure with these port matched heads. I hadnt touched anything but stock to stock parts swaps in the last 3 years. I dig this project back up and first thing I buy bam, doesnt fit. Forgot how aggravating it is with aftermarket stuff.

Had to redo a set of tti headers with the same issue.

Well crap. Even TTI's?

Yes you did... You'll likely need to add material to the header port sealing surface.

There are two port sizes on small block heads, The 273 size, which is smaller than the 340 size ones. In fact the stock manifolds on my 87 Diplomat were very close to not sealing on the stock heads on my 65 273, top to bottom, maybe 1/8" overlap total. Both were untouched openings. I suspect those headers have the small port openings.

All you can do right now is make an adapter plate that'll seal to the head and the headers, short of buying new headers or heads. Which will kill the idea of gasket matching.

Unless the overlap at the top of the port is enough that you can oval the mounting holes and drop the header down to seal?

weld a bead around the header port making it wider then have the header flange resurfaced.

Thought about slotting the bolt holes vertical to shift the opening up. My other thought was if a machine shop could surface the raised area flush down to the 5/16" thick flange area and basically turn it into an exhaust manifold type seal. But how/where are the tubes welded to the flanges? Are the tubes pulled through hammered out then weld bead built off that is now my gasket area? Or is the pipe welded inside the opening of the flange? Only then could they be surfaced.

I have seen them welded around the flange and the tube on gasket side.

I have welded up a couple bent headers that leaked at the flange/tube side by filling the gap in the flange around the tube.

if you look that's how they are welded up to start with.

just make the bead wider around the area you need and a machine shop can surface them flat again making a large sealing area.

result will vary.