My Coupe developed an exhaust leak last Fall before I put it away for the Winter. I took the manifold off this morning and this is what I found. I couldn't believe how the green gasket disintegrated. It wasn't on there that long. By comparison I included the copper gasket in the picture that I took off another engine. Looks like copper is the way to go if you don't want to use the standard rings.
Dan - perhaps yours fits better but personally I've found those triple port gaskets to fit miserably on my engine. The holes weren't really in the right place and neither were the grooves for the gasket to hang on the manifold studs.
Try these before you do anything else: http://www.snydersantiqueauto.com/4829
I went with these and will never use anything else. And heck, with the way they've held up and then been able to be cleaned and used again and again, I might not need new ones for a LONG time. They are well worth the cost as I've removed my manifolds and just wire brushed these clean and used them again multiple times and I have no leak problems.
Leprechauns!!! It is March.
I find these stock gaskets to be fine https://www.modeltford.com/item/3063-64.aspx, and they cost a LOT less than the others. If there's any rust pitting on the engine surfaces, you can help them seal with some high-temp sealant.
In the case of a warped manifold the Lang's catalogue offers the choice of (1) a new manifold or (2) one of those crappy one-piece gaskets that did you dirt. They don't mention the third choice: http://mtfctulsa.com/Tech/manifold.htm
I don't know if they have any left, but Snyder's was offering a substantial discount on "scratch 'n dent" new exhaust manifolds. I bought one and its only flaw was a small grinder mark in an area that doesn't show when the manifold is mounted to the engine.
The rings work best because each port has its own gasket. You do need a straight manifold to use it. It's a little harder to install with the copper rings, but I have been able to use all 3 left hands to hold it in place while using the one right hand to tighten it! Always use the steel rings whichever type gasket you use. The steel rings will hold the manifold in place and be less likely to warp.
Seth, Next time i place an order, I will try them. This is what I have in stock now. I tossed the green in trash. You are correct on the copper ones, they don't fit over the studs very well. The old ones I had in my original picture seem to have sealed well around the ports. I'm not fond of the original style rings as over the years I've had them burn out. I use the glands in whatever I use. I also file the exhaust manifold ports to get rid of pits, and then put a coating of mega copper gasket to seal, good to seven hundred degrees(available at Langs).
Norman, I made a tool to hold the exhaust manifold out of two old manifold clamps. Shown in second picture. I line the exhaust manifold up and hold each end with these two clamps. I then line up the intake manifold and install the clamps. This makes it an easy one man job.