If you bought your headers new and they include new gaskets then this really isn't a concern for you, but if not listen up! I had a set of new hedman's that a purchased from a guy who hung them on his garage wall and never used them, so the gaskets were long gone. I was detemined to have no leaks, so I purchased some $30 copper gaskets thinking I was doing really good and had that part taken care of. Well, after spending 7 hours installing the headers and finally getting to the point of starting the truck for the first time, I was severely dissapointed when they leaked terribly. Here's a pic of the gaskets I took out today.
I couldn't understand it, but figured it out shortly. It turns out that there are TWO TYPES of mating flanges on headers, and you have to have the correct gaskets to match! You can see where every port on these gaskets was leaking; that's because my headers have a bead welded on the mounting face around the port, which is then ground flat where it's supposed to seal to the head. The "bead" just sat inside the gasket holes and leaked all over the place. These gaskets are made for thick flange headers that have a smooth, flat mounting surface.
The lesson that I am preaching here is that if you have headers and you need gaskets, do some research! I purchased some gaskets that are made by Remflex and are designed to work with welded bead type headers. I also know that Flowtech makes a gasket set for the same type of application.
Well, that's about it. I just wanted to share my experiance so that none of you go through this headache like I did. Buying the proper style gaskets in the first place will make your life much easier!
