I did add a pressure gauge a couple of days ago but when I initially set it I just cranked the valve all the way in and then backed out 3 full turns as a guess. The shop next door allowed me to use there pro gauge to check it the next morning and that's where I got the original reading from. Since adding the "permanent" gauge I have a consistent check if I need it. Since the Holley has dual outputs it's easy to add-on. Additional parts other than that was the 3/8th's NPT to what ever size fuel hose that you're using and either the gauge or a cap to close the second output. After you do this; clean the carb from carbon the best you can (carb cleaner, steam trick, etc..), check your timing and use the Weber initial set guide for Fuel/Air and Idle.

Cheers!