The Stovebolt Site Forums The Shop Area Engine Shop 216 engine manifold leak

I have a 1940 Chevy 3/4 ton special with an original 216 engine (rebuilt). I have a leak around the manifold around the 2nd and 3rd exhaust port.(I can see black exhaust carbon around this area) the bolts are torqued down well beyond any reasonable manner, gaskets are new, tried to double up on gaskets, no avail. Suggestions?

You may need to pull the manifold and put a straight edge on both the manifold and the head. I have seen one or the other or both eroded to a point that a gasket would not hold.

To add to what Dave said (he helped me with mine) be certain to clean-up each bolt really good with a wire wheel or thread die, also run a tap in each hole to clean it out good

I had the same problem with the two center ports leaking
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I had a machinist deck it for me taking material off the ends then skimming all.
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No more leaks
Over torquing can crack the manifold

Could the lack of contact of two inboard exhaust ports be caused by the intake manifold being a smidge too proud toward the head preventing the exhaust ports from sealing? If this is the case, maybe loosening the two bolts and two nuts that hold the intake to the exhaust together, then bolt it to the head without the gasket for the purpose of aligning the manifolds. Once the the hold down bolts are tight, tighten up the two nuts and two bolts. Use a thin feeler gauge to check for a good fit at the exhaust ports. If everything is flush, take the manifold assembly off and reinstall with the gaskets and check for leaks. A hose held to your ear works good for hearing exhaust leaks.