I have some headers to replace my stock manifolds (which are leaking). When I bought the headers, they came with stamped copper gaskets. Should I use these or look for something else? I also have some copper/carbon layered gaskets.

 

Which truck?

If its the Silverado id use the stock ones.
For the ford id use Percys.
http://www.percyshp.com/xxcarbon.html

 

Sorry, its the Explorer. My stock gaskets didnt hold up with the turbo.

 

I've always had good luck with fel-pro exhaust gaskets.

 

In that case Percys again
They wont deteriorate with the heat.
And for a bonus there not expensive.
http://www.percyshp.com/pricelist.html