Vacuum source for distributor


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By Bruce Compton - 13 Years Ago
I've finally changed my distributor to a dual advance one  but the Holley 4000 has no vacuum port to supply either direct or ported vacuum. I would prefer to use ported vacuum, but can see no way to get it. Rather than "T" off the line to the wipers for full manifold vacuum, I'd like to add a fitting to the spacer plate to provide a separate supply, but don't know whether to tap into all four holes or just the front two. Any ideas?? Thanks : Bruce
By oldcarmark - 13 Years Ago
You should be fine using the same vacuum source as the wiper motor.I have my "motor minder" vacuum gauge and distributor tee-d together.Prior to the vacuum hose going to the fuel pump if the dual action pump is being used.Not on the hose going from pump to wiper motor.
By stuey - 13 Years Ago
i would sugest the front two

wiper motor tee if the wipers run direct from manifold maybe not if they come via the vacuum/fuel pump

stuey

By Ted - 13 Years Ago
Bruce Compton (12/8/2012)
I've finally changed my distributor to a dual advance one but the Holley 4000 has no vacuum port to supply either direct or ported vacuum. ......
The distributor vacuum source for the Holley 4000 four barrels can be found on the front of the carb just under the air cleaner base.

 

Up until recently I thought that all '56 and earlier Teapots incorporated both venturi and ported vacuum to the distributor but have found another exception to this.  While the ’56 Teapots have an anti-spark valve to accommodate the Load-O-Matic distributors, I have looked inside a List #1162 carb recently to not find the venturi hole in which to plug to make this particular carb ported vacuum only.  Without the venturi port, this carb would have only the ported vacuum signal but I'll have to do more looking to see exactly what the anti-spark valve actually does then.  It would appear that the internal vacuum porting on some of the ’56 carbs was changed when the distributor went to using a dual pod vacuum advance chamber.  It looks like a project now to disassemble a ’55 Teapot carb and verify this particular scenario.