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Is there any reason a Mc-30 intake manifold can't be used on a Mc-6. I was looking at the schematics and it appears that the gaskets are different, manifold to block. The 3rd port opening isn't cut out for the Mc-30?

Mac 30 (and 40) are third port engines. The opening in the crankcase on the Mc7, Mc30, and newer engines is deeper than on the Mc6. Many Mc30 manifolds have the reed opening positioned low enough that it will miss the Mc6 crankcase hole. You'll have to check. Otherwise, there's no reason you can't use the later manifold. You CANNOT use the Mc30 gasket on an Mc6!

Thanks Ted, will cutting the small portion of the gasket separating the 3rd port be necessary? Thanks again.

Mc-30 manifold won't fit an Mc-6 without modifying the Mc-6 somehow.

Thanks, Tom. I didn't have a '30 manifold to look at without driving over to Ron's house. Dominic, sometimes you get lucky with reference to the location of the reed opening as it exits the bottom of the manifold. A few of the later third port manifolds will still work on the Mc5, Mc6, Mc10 and Mc20; a lot of them will not. If you DO find a manifold which will open into the engine, not to the atmosphere, you still want to use the Mc6 gasket without cutting it. That way the third port still works. If you feed carbs thru the stuffer, you need to block off the third port in the engine, or you'll experience spitback thru the top carb. You can do mods and make strange combinations work. I just modified a 1960 Hovey dual carb manifold with JB Weld to feed two flatback carbs thru the reed for my 101. I filled the third port area of the manifold.

Intake Mac-30...