Vacuum Gage & Tachometer - C2 L79

[bill #36445]

I want to do a minor tune up on my 65 L-79 and the Service Manual says to hook up a vacuum gage and tachometer to set the idle mixture setting (very reasonable and to be expected); however, I can't see a manifold vacuum port at the base of the 2818-1 Holley that my car has. Most Holley's that I've seen have a vacuum port for manifold vacuum located on the baseplate. Where do you hook up a vacuum gage for this set-up? Also, what is the best way to hook up a tachometer to monitor the idle speed during this procedure?

Thanks,

Bill Jennings

[William C.]

Re: Vacuum Gage & Tachometer - C2 L79

The 2818 has a manifold vacuum port on the passengers side, where the vacuum advance is connected. It is in the upper area, not the baseplate. The easiest way to use it is to "T" the line to the vacuum advance.

[Wayne K.]

Re: Vacuum Gage & Tachometer - C2 L79

Bill,

As Bill has mentioned configure something to T into your vacuum advance line between the distributor and carb. Your dwell/tach meter should have connection instructions using the coil as a connecting point.

Wayne

[mike geary]

Re: Vacuum Gage & Tachometer - C2 L79

Bill: I remove the plug in the manifold, on the top surface aft of the carb, and install a vacuum hose fitting that I think I found at Ace hardware. Then I adjust the idle mixture, looking for maximum vacuum level. Haven't found it necessary to monitor the RPM.

[John H.]

Re: Vacuum Gage & Tachometer - C2 L79

Most dwell/tachs connect the red wire to the coil (-) terminal (where the black primary wire connects from the distributor), with the black lead to ground, but check your instructions in case yours is different.