How to hook up Ford Motorcraft 4300 carburetor!

Dec 17, 2005 2 Replies

Want to know if the tube sticking out of the back of a Motorcraft 4300 carburetor (Ford 429)directly underneath the Hot Idle Compensator should be hooked to vacuum hose or something!



Caveat: From a guy who HATES carbs!

The real question is: What vacuum lines on your engine are un-connected?

Almost all ports on a carb reflect either manifold vac or air-flow through the venturi's. And noone should be tuning a carbed engine without a vacuum gauge..

Hook a vac gauge to the port, does the vacuum increase or decrease as the engine is put under a load and throttle opened?

My thoughts: just cap it off

I have the manuals for 1971 but it's not clear-I think it may be the vacuum source for the air cleaner doors...

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