Minimum would be a Vac/Boost guage Tee'd into the 11/32" brake booster hose coming out of the back of the intake manifold.
Autometer sells the guage and A-pillar pod
Pep-Boys has the Vacu-tite tees, elbow adapter, and hose.
I used:
Autometer Vac/Boost gauge - $50.00
Autometer Volts guage - $45.00
Autometer Dual guage pod from
http://www.raceandstreet.com/ptindex
Hallman ES boost controller (Fixed by me) - $50.00
11/32" "Anti-smog" hose, Vacu-tite! universal tee, and a vac elbow from Pep Boys - $10.00
Double check that boost controller prior to install by blowing through the boost/pressure side whilst you adjust the knob.
Find right where it goess wide open and mark it with a sharpy/permanent marker and then test drive. Adjust using 1/8 turns or smaller and always lift the gas pedal quick if it zooms past 15PSI.