If a piece of 3/8 "stock" fit (3/8 NC) just get a new 3/8 NC manifold stud at your local parts store and use it. If you have to enlarge the hole in the manifold slightly, then fine.

I am not understanding the problem. Seeing as it's the back stud (nearest the firewall) the only thing it holds is the back of the exhaust manifold so no trouble with the intake manifold. Heck, all of them could be 3/8" and cause very little trouble.

OK, if the old piece of "stock" pulled out the threads in the head then there's an issue. Then have a 3/8" helicoil or (better yet) a solid insert to take it back to 5/16" Can't recall the brand name of the solid type inserts but they were pretty common for aluminum work (and use a MUCH larger hole!).


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Mike!