Questions on V6 vacuum system

eaglecap

Member
Jul 31, 2000
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I am rebuiling a 1975 2.8 V6 with 4 speed tranny. I have decided to disable the EGR valve and to run the vacuum from the carb straight to the vacuum advance instead of thru the ported vacuum adapter. According to the write up the purpose of the ported vacuum is to directly apply exhaust manifold vacuum directly to the vacuum advance to increase idle speed if the engine starts to heat up when idling. The EGR is just a air pollution pain. However there is a valve on the drivers side of the engine that connects to one of the vacuum ports. This valve closed off the exhaust from entering the exhaust pipe. I cannot find any information as to what the purpose of this unit is. Anyone know what it is for and if it is really needed or just another pollution gadget.

Any input on the other pollution components that can be removed from the system to get better performance?