[Woodchuck]

Exhaust leak.

 

[Woodchuck]

Removed header gaskets and they are bad. New problem. The header port is oval and the ports on the engine are rectangle. Doh. Which port gasket should I use?

The one that seals all the way around....

 

[Woodchuck]

ofcourse. But should I match the header port that is oval, or the port from engine that is rectangle. I’m guessing a rectangle to catch the corners?

It doesn't matter as long as there is a mating surface between the header flange and cylinder head all the way around the port of sufficient width to seal it.