Exhaust Ports Misaligned???

[stu in wichita]

I finally tracked down an annoying exhaust leak to an unlikely cause. The #7 port in the exhaust manifold don't match the port in the head. The engine is a 318 out of a 1970 truck with the original truck manifolds.

Compared to a gasket, the shape and size are correct, but the position is about 1/4" too far back. The mating surfaces are nice and flat. The misalignment is obvious when comparing the compressed area on both sides of the gasket.

I assume it's a bad manifold casting due to core shift or something. It almost couldn't be the head, right? I've never heard of anything like this. I tried building up the area with weld and resurfacing it. It sealed a little better (new gasket of course), but the tik-tik-tik is still there, especially until it warms up.

Any ideas?

 

[moparleo]

Did you by chance take any pictures while it was apart ??Would be a lot of help. We didn't see it so it is hard to answer your question.

 

[Chryco Psycho]

I always have to port heads & manifolds to line them up , I always make the exhaust manifold larger than the head so there is no ridge the airflow runs into . So it sounds like you have an extreme case & likely have to replace the exhaust manifold to correct the problem or find a very different gasket to seal it up.