Manifold Vacuum Test/Tuning

[65 Mustang]

Hello everyone,

Looking to test manifold vacuum pressure for first time and possibly tune car using it. My issue concerns placement of vacuum gauge. I was told it should connect directly to intake manifold and not a port on carburetor. However, I only see one opening on intake manifold and it is currently occupied by a line leading to transmission. Can I simply disconnect that line and put the gauge in there? Do I need a splitter of some sort to accommodate both lines simultaneously? Thanks for the help

 

[JackFish]

What I would do is insert a tee in that line. It's probably a bit larger than the one on the guage so you might need an adapter.
You can get a universal tee that fits different size hoses:
http://shop.advanceautoparts.com/p/dorm ... /5019672-P
I've run a hose up to a guage clamped on the steering column so I can see what's going on all the time.
It can teach you a lot about what happens under different driving conditions.

 

[65 Mustang]

That's a good idea. I wasn't thinking of keeping the gauge permanently on but I can see how that would be beneficial. If I just wanted to get a sense as to what the pressure currently is, do you think I can just momentarily disconnect the transmission line from the manifold and plug in the vacuum gauge? I'm just wondering if removing that line would affect the results or possibly hurt transmission. Thanks.

 

[JackFish]

No problem with that, for sure use that line. No need for a tee.
It won't affect the transmission especially since you're not driving around.
It's for the vacuum modulator on the tranny, which senses the load and affects shifting.

 

[65 Mustang]

Ok. Thanks so much for the info. Appreciate it.