I need some help asap, since my friend is coming soon to help me install them. Which is the front and back? I read in a post that one flange is almost 90degrees, and the other is around 75 degrees, but I don't remember which was the front and back. I can't find that post now. If someone knows, please help. Thanks!

 

r u talking about the actual headers or the downpipe? I think both headers can go on either way, doesnt matter where u put each.

 

What brand?

If Comptech, the labeled header goes on the front.
If OBX, labeled header goes on the rear.
I don't know about other brands.

But in general, assemble the entire system while it's off the car, and the front header should sit almost straight up, whereas the rear header should sit at an angle, leaning toward the back of the car.

 

It can only go one way. anyone who says different has never done this install.

The best way is to just test fit them. Once you put them on, you'll see which one is the rear an which is the front.

 

ok, well I put them on the downpipe, and you can see by the angle of the header openings, which is which. It wasn't complicated to install, but difficult to get some bolts. Especially the last bolt on the front that sits next to the alternator! Also, how tight should all the bolts be? Is there a specific setting? I don't want to break or strip anything. I'm still getting a metallic hissing sound, so I guess it's not tight enough. Or, maybe the gaskets need to settle?

 

If it's a constant hissing sound, then it's normal. If it's a leak, then it will sound like "pff, pff, pff, pff"

The hissing sound is due to the thinner walls of the pipes -- they don't kill the noise as well as the thick cast iron factory exhaust manifolds.