Reddit reviews AUTO METER 2337 Autogage Vacuum Gauge Panel,2.3125 in.
We found 1 Reddit comments about AUTO METER 2337 Autogage Vacuum Gauge Panel,2.3125 in.. Here are the top ones, ranked by their Reddit score.
Includes bulb and socket assembly with red and green bulb covers
You can also use a vacuum gauge
https://www.amazon.com/Auto-Meter-2337-Autogage-Vacuum/dp/B00062YVT8
The closer it is to zero at wide open throttle, the less restrictive it will be.