Couple questions. One is it hard to change the gasket on the exhaust side of the headers? Does a stock gasket work with headers or does it need to be something special? Thanks for any help. Trying to figure out where this knock sound is coming from.

 

When you say "on the exhaust side of the headers" are you talking about the collector (the outlet)?? Or are you talking about where the header bolts to the cylinder head?

To try to find a knock sound take a length of tubing, put one end up to your ear and the other end around the joints of your exhaust, and around the header flange. You'll hear where the knock is coming from when you find it, and you won't burn your face/ears

 

Is it a knock or a ticking? Usually a ticking sound is associated with leaking headers. You can use copper gaskets on headers, but I chose to go with Fel-Pro gaskets.

 

Percys dead soft! My headers were used and the flanges looked iffy and they sealed up. Got them at AutoZone.

 

I used Fel-Pros sprayed with a copper adhesive. Never had a leak. Also, did you verify that you didn't have any loose exhaust bolts?