FiTech EFI system

Is there a way to calculate how much vacuum s/b present at the throttle body ports?
I hooked up my factory Performance Indicator gauge and it doesn't work, it did with the carbs. I pulled the hose off and the idle didn't change, put my finger over the port and it doesn't feel like it's pulling a vacuum at all. I remember when I installed there seemed to be some distance between the manifold opening and the port, but there was a long channel in the bottom of the throttle body.
Now I'm thinking my vacuum advance would suffer from the same issue.
I'll check it with a gauge when I get home, but I'm thinking if I pull the throttle body, the gasket will show the port channels, and I can drill holes down thru the intake into the plenum. It is a tunnel ram and there is enough material there. At idle it's sucking gobs of air thru the air cleaners.
I just want to sort this out before I start fine tuning, as I discovered already, cover the basics first.