Originally Posted by macrs

Had exactly the same thing mate!

Fitted SS manifold with a 'motorfactors' CVH Turbo gasket and it blew it instantly. I then got an original Ford gasket from Matt Lewis Motorsoprt on t'internet...and it's still holding fine.
There was quite a difference between the gaskets. The original one has solid 'Fire Rings' around each port and the cheaper one did not. The rings would appear to stop the gasket compound material from being blown out...

That's my theory anyway and it worked for mine! Just out of interest which manifold have you fitted??

Hope this helps!!!