I would place the needle on, say pointing at zero. Then I would run it on a drill at a constant speed and record the number of miles travelled over a specified time. Then you calculate the speed it was supposed to be and this will tell you how accurate that one point in the total range is.


1951 GMC 1 Ton Flatbed -- It is finally on the road and what a great time I have driving it!
1951 1 Ton Completed


My Chevy Master 4 Door is on the Road!