Originally Posted by SSedan64
Some Modulators are adjustable, small screw inside tube where Hose connects. It will give a small 3-5mph range.
For more adjustment you'll need a Governor Recalibration Kit.
B&M Governor Recalibration Kits 20248 - SummitRacing.com
Modulator needs Full Manifold Vac, not Ported/Timed Vac source.
Yup ... I'd start with connecting the vacuum line directly to MANIFOLD vacuum.