Source for Boost Gauge

So I have a roush SC on a ‘12 BOSS 302 with the 80mm pulley. I’m looking for a vacuum/boost source I can “T” into for the gauge.
Being that this has the 80mm pulley, and Kooks 1 7/8” long tube headers with catless mid, what ballpark should the boost be in?.
The exhaust is factory past the mids by the way.

There should be a vacuum line on the blower, T into that.

https://lib.americanmuscle.com/files/101173-manu.pdf

Look for the location of the line for the bypass valve.


Like mistletoe, I’m hung where you will see.