If your main goal is to cut underhood temps, go with the header wrap. I'm got a ceramic coated cross-over and that thing still gets hot. I touched it after the car was runnung for a while. that hurt. But i've heard with header wrap that you can actually put you whole hand on there and not get burnt.
But, if i'm not mistaken, header wrap locks moisture in and deteriorates(can't spell) the manifolds over time.

that'* why the sealer is a good idea

And the Series 1 manifolds are Stainless Steel, not cast iron like yours.

Ohh wasn't too sure if the moisture was blocked in to begin with or got trapped over time.

I figured the manifolds were some kind of steel since they are tubular.

I removed mine and cleaned ip the ports on them. I didn't have any gaskets at all so I can confirm the 1992 didn't have them. I used the top grade Felpro gasket when I reassembled.
As for porting, I didn't have much at all to port. I removed a few welding bumps
and that was about it. I was really suprised at how good they looked inside.
If my SSEI hadn't have had an exaust leak I would have never done it.
The back one was a @$%$@&$@* ! to put on.

JLathem

Jlathem, from my experience, what you have found is exactly the normal situation: That is, GM engine plants in general do not use any gaskets on the exhaust manifolds. (at least on their V-type engines) And I have also found that almost all (if not all) aftermarket gasket sets include gaskets for the exhaust manifolds.

Also, on the ceramic coatings, I have used on steet tube headers, I really didn't notice hardly any decrease in the external temperatures. If it were me, and I decided to do the ceramic coating, I would still darn sure re-use the heat shields. If you don't, you will be asking for problems related to radiated heat from the manifolds. -By the way, you could have your heat shields coated too- -they would look better,,,

And the guys are exactly right about the heat tape. (header wrap) It will greatly reduce the extermal surface temps. Just be prepared for accelerated deterioration of the headers/manifolds themselves over time, due to much higher internal operating temperatures of the manifolds. And, depending how tough the parts are, you may never experience the deterioration.

Good Luck !!

Oooops! The rear manifold is now without it'* heat shields and most of the shield mounting points It seems that a die grinder had it'* way with it this afternoon.

Well... my next mod... custom heat shields!

Nearly ALL header manufacturers warranties are voided if you use header wrap. It'* generally because it hurts them over time thru the heat trapped, and moisture as mentioned.

How bad is the header wrap? Because I'm thinking this is something I will do.. my car is 16 years old.. and I don't want my headers melting because I wraped them.


-justin