If the manifold happens to get installed without one of the alignment rings, or the ring is a little too wide, a vacuum leak is a very likely result. Sometimes if a manifold has been milled or leveled on a belt sander, etc., the ring needs to be shortened as well or it prevents the gasket from sealing.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
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