As above, definately not. If You connect a vacuum gauge there it will last about half a minute. Less if you rev the engine.
In total there are 10 different places you could measure vacuum. It depends what you want to do. If you want to balance the throttle butterflies then you will see there is a separate spigot on each intake TB directly above where each tract meets the cylinder head. If you want to measure each bank then the take-off point is under the plenum, behind each TPS. You need to pull the vac hose that goes to check valve and then to the vacuum tank. I can't post pics because I'm sitting in a hotel miles from my car and PC, otherwise I would.
I'd like to test engine vacuum operating the bypass valve. I have inserted a vacuum pressure meter into the system, but after the solenoid. Since vacuum is not called unless the solenoid activated I am unable to determine whether bypass valve failure is result of the solenoid or vacuum leak.
