Nissan Repair: exhaust manifold gasket, stock exhaust manifold, nissan 300zx

Question
hi, i recently purchased a 1993 nissan 300zx (NA)that had the wrong exhaust manifolds installed on it. i found some stainless steel amz headers on the internet and bought those as they were about 1/2 as much as stock manifolds. i installed new o2 sensors in the headers while i had them loose. the r/h side went on with no problems. the drivers side though has been a job. i noticed that the l/h manifold gasket supplied with the headers had separated. it looks like 2 manifold gaskets now. (one side is metallic looking-the other side normal gasket material). can i still use this?  if not can i use a new gasket for a stock exhaust manifold. (i have 2 of these new laying around that i purchased from nissan a couple of weeks ago.

Answer
Dale,

If the seperation you are talking about is between the header tubes it is fine.  The gasket is a composite of both metal and asbestos.  If you have an exhaust leak the factory gaskets are fine to use.  The big thing to remember is not to tighten the bolts too much or you will warp the headers.  So, use a calibrated wrist to cinch the bolts without over doing it.