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I'm putting a holley 4bbl carb with vacum secondaries on a freinds 79 f-150 with a 351M in it and i was wondering what to hook the vacum port for the secondaries up to? pics would be helpful too if you have them Thanks
Do you have a pic of the carb? Holley carbs don't have an external port for the vac secondaries. It's an internal vacuum passage.
Some carbs have a tube that runs out of the passenger side secondary barrel. That tube is above the venturi. It's purpose is to provide a clean air intake for the heat riser to the automatic choke. There should be a hose/pipe from that tube, down to the passenger side exhaust manifold and another pipe from the manifold up to the choke housing.