I'm having a couple different issues with my new exhaust set-up.

Headers are used Hedman shorties, I believe they are about 7 years old. These are not cheap headers, but unfortunately have warped on the flange which connects all the primary tubes.

I went ahead and installed them using the gaskets I received in my Fel Pro master rebuild kit. They leak pretty bad, especially from the number 2 cylinder, and where they meet up with the Y pipe (both sides). The leak at the head makes quite a racket.

I've heard of people cutting out the flange between the primaries, I was considering doing this and then maybe filing the remaining flange sections flat. I'm also somewhat convinced that I should scrap the idea of using gaskets and just go with Ultra Copper silicone sealant. Thoughts?

The second problem is where the headers meet up with the Y. The flanges here are all bent, so they don't squeeze the gasket well. I've tried double graphite gaskets with a ton of high temp. silicone, and they still appear to leak. I'm wondering if anyone has had any luck pressing the flanges back into shape with a shop press, and what kind of gasket/sealant set-up actually gives a positive seal? These are the tri-bolt flange style.

I'll probably rip the headers out tomorrow, so feedback before then is appreciated!

 

Welp.....I cannot tell you exactly what the problem is that you have...but what I can tell you is that I had the same problem once (leaks at the y pipe/header flange and header/head flange. After much trial and error, I found out that aluminum gaskets would not seal at the y-pipe, but copper gaskets did. Then it was the exact opposite at the head. Copper gaskets would not seal but aluminum ones would. This may not solve your problem, but I guess the moral of the story is...some gaskets/materials can seal differently on a case by case basis.

 

Have a machine shop put the headers on the big belt sander to flaten the flange a lil bit.

Next, ditch the cheap O steal backed paper gasket and use a felpro 1404 or 1405, 1" long header bolts and a lil dab of anti-seize on the threads. no more probs

 

The flanges are quite wowed out in the middle sections, I'm not sure if you could just put them on a belt sander. It seems like they need to be either cut, or pressed, back into shape. I haven't cut them apart yet because I'm worried the bolt holes won't line up.

The strange thing is, even though I can hear what sounds like a bad exhaust leak, when I dump a bunch of seafoam through the booster line, I can't see any white smoke coming from the headers. Before, it used to smoke quite bad when I did this. Now I can't see anything at all.