Run vacuum line thru firewall under hydro booster.
I Teed mine off the Boost selenoid. Looking at the Eaton from the driver side, you'll see all the selenoids, etc.. on a bracket mounted to side of Eaton. Far left one toward front of car. Tee off that vacuum line connecting to that selenoid. I used a piece of vacuum line from auto parts store to end of plastic line off guage & slide that hose onto the Tee you'll get from auto store. You will need a couple inches of the line that connects to selenoid to fit from the tee to selenoid.
Not a bid deal. I have my Whipple set-up that wat too.