I believe the gauge is pretty accurate, being what I saw on the dyno through the rpm range
Was consistent with that I seen on this gauge when I put it in the truck.
FWIW the idle wasn’t this rich when I first installed the engine. Which leads me to believe it is something I am doing wrong.
I installed this on my cuda and had to make adjustments then put it back on the truck.
It doesn’t seem to run rich at idle on that motor which is a 410” with big Indy single plane and much bigger cam.