Question about exhaust manifold gasket

[Buttanic]

I am putting a closed cooling system on the 5.7 Chevy I am building. I am using Mercruiser center rise exhaust manifolds which will be closed cooled also. The Mercruiser parts breakdown shows only gasket 27-863725 is used to block off the water passages between the manifold and exhaust elbow.
I am not real comfortable using just the gasket material. I am thinking more about some sort of metal block off plate sandwiched between two gaskets.
Any thoughts.

 

[Bondo]

Re: Question for Don or Bondo

Re: Question for Don or Bondo

Ayuh,...

When I get that far,... I'm going with dry joints...


Btw,...

 

[FreeBeeTony]

Re: Question for Don or Bondo

Re: Question for Don or Bondo

Not sure of the P/N........but if it's Mercruiser's new "block-off" gasket, you don't need the SS plate. I used them on my set-up w/o any problems. Just make sure it's the one intended to block-off the manifold from the riser.

 

[Don S]

Re: Question for Don or Bondo

Re: Question for Don or Bondo

The Merc gasket (27-863725) is more than gasket material. There is a thin SS shim between the two gasket surfaces. They have been working fine for Merc users for many years.

Here is the service bulletin on gasket use.
http://www.boatfix.com/merc/Bullet/99/99_10.pdf

 

[Buttanic]

Re: Question about exhaust manifold gasket

Thanks Don