[RRF]

I am in the middle of re & re my RAIII exhaust manifolds. Last install I did not use any gasket, just thin smear of exhaust sealer, and bolted it up. No leaks for a couple years.

This time I have the blue Felpro gasket, but I would like to cut out the areas between the ports, by placing the gasket on the heads, tracing the ports, and cutting the excess out.

Next step would be to use a bit of spray adhesive to hold gasket to head, add a thin smear of copper RTV to manifold side of gasket, and bolt up the manifold.

Good or bad idea...?

[RRF]

I am in the middle of re & re my RAIII exhaust manifolds. Last install I did not use any gasket, just thin smear of exhaust sealer, and bolted it up. No leaks for a couple years.

This time I have the blue Felpro gasket, but I would like to cut out the areas between the ports, by placing the gasket on the heads, tracing the ports, and cutting the excess out.

Next step would be to use a bit of spray adhesive to hold gasket to head, add a thin smear of copper RTV to manifold side of gasket, and bolt up the manifold.

Good or bad idea...?

[quicksilver97ta]

Port matching is a good idea, but if your using manifolds why not just use the metal gasket with no sealant? I just R&R's my manifolds and used new felpro metal gaskets like the originals.

[RRF]

..gee, I always thought "port matching" referred to matching the actual ports to each other...ie: grinding required. So I am on the right track..

The blue Felpro gaskets have the metal insert...the new felpro metal gaskets you are treferring to, are these just the metal "shim" type? or are we talking about the same piece?

[quicksilver97ta]

Well sorta on the "port matching". Matching each to the gasket is just the easiest and most common way to accomplish a match.
Metal shim type, thats all you need, thats all I've seen for manifolds. They are the standard replacement gaskets. Maybe your application pulls up the ones you describe for some reason. Either one should work, the metal part is whats important. Mine are felpro and I think were around $10, all I asked for was "exhaust mainifold gaskets for a '70 lemans".

[buwalda]

I would use no gaskets with a smear of silicon, as you did originally.
No gasket = no possibility of gasket blow out because there isn't one to blow out or leak!!
Some manufacturers, such as Chrysler, NEVER used exh a gasket to seal the exh manifold to the head. I had many of them & never had any problems.
With port matching the manifold to the heads, the port opening in the exh manifold should be a little larger all round than the port opening in the head, about 1/16". This helps reduce reversion.
Good luck.