I want to install a temporary vacuum gauge and I'm not sure where to hook it up. I have a L28 240Z triple 40 DCOE-18 weber set-up with a cannon intake. The only place I can think of installing is at the brake booster but have read not to do it there?? I don't want to drill and tap a hole. Why can't I use it at the brake booster?

because you will loose the braking assist, making it difficult to stop. If you are not going to drive the car and just want to have a vacuum gage connected for a test . Go for it. I wouldn't drive it this way .

Like beandip says, if you ever want to install a vacuum gauge for anything more that tuning while the car's stationary, put it before the brake booster.

The biggest problem with doing it with triples is the fact that installing it on one manifold may be ok, but can you guarantee that all three carbs are perfectly in sync? If not, then I wouldn't bother installing one full stop.

Why do you want to install one?

No reason you can't put a T at the manifold in front of the booster line and attach your gage there, won't hurt anything. I have a T there on mine with the pcv valve connected there.

Cool thats what I will do, T it off of the brake booster line. The reason is that everyone keeps telling me to check vacuum pressure as a means to troubleshooting my other problem.