I'll check mine, but I would expect it to be fairly high, like 20 inches or so. If you are seeing much lower, might be a problem.
You can hook it up in place of the Optispark vent vacuum source on the drivers side of the intake in the middle. Do it direct to the manifold.
I'll check mine tonight and let you know what mine does for a comparo. Anyone else with a 94-96 LT1 can give some idle vacuum readings for a good comparisson?
Short term fuel trim is the new name for the Integrator (look for my posts for it on the 4.9L forums and Deville FWD). The Long Term Fuel trim is the Block Learn value.
Basically the STFT is the digital A/D representation of the O2 sensor output, digitially interpreted. So it is a combo of O2 cross counts and O2 voltage in an value the computer understands, 0-255. The LTFT is the same type reading, but it is the offset for the STFT. So if the STFT is running an average of say 155 (lean adding fuel) all the time, (leaking intake gasket, etc) the LTFTwill correct for it by coming up to 155 or so (lean adding fuel), and the STFT should return back to 128 average. These numbers fluxuate, so it isn't like you do this to one and the other does this, they vary, so you must look at them and do some good averaging in your head on where you see it the most.
So this will give you a clue on if there is leak or not.
It is normal to see the STFT go high under acceleration (150-160) and low under decel (80-90), as the ECM struggles to compensate. As it gets ahold of the corrections, it will start to return to 128.
The one that tells the most of the LTFT, as it shows what is being corrected, if all is being corrected, the STFT should look close to 128.