Vacuum Gauge

[DITCHPICKLE]

Where is the best place to splice into a vacuum line to instal the "T" for a vacuum gauge?
Thanks
Steve

[dave571]

The best thing to do, is to put it onto one of the fittings on the vacuum tree(where the main booster vacuum goes onto the manifold) If there are no empty fittings, switch out the tree for one with extra's.

Another option is to put the line on to a capped off one on the carb, if there are any.

[Hammer 74]

You can not just use and extra capped off port on a carb. It has to be as low as possible on the carb, usually on the base of the carb like where the power brake booster port is. Higher up the carb is a different vacumm source. If it is a Holley they usually have a port on the front right just under the front bowl. This port is for a guage. Other carbs have ports for the same reason since vacumm is a good way to tune the idle mixture. If you are not sure which one to use just unplug a low/base port and hook a guage up to it and see what it reads. A stock motor should read between 13 to 17 inches of vacumm. If the port reads low then goes high when you stab the throttle then you have a distributor advance port which should be higher up the carb than the base. If it looks like a good port just tap into it. It is difficult to find a fitting to reduce a booster line down to 1/8" hose. Hope this helps a little.