Yes they are the same as the later model units. Each are gear driven from the output shaft of the transmission to a cable. The cable spins a small magnet in the speedometer head. The needle is hooked to a very light spring which holds tention. As the magnet spins, the needle trys to keep up only the spring holds it back. In these three items is the calibration. Each have to be correct for the gauge to read correctly. 90% of all speedometers operate on the same ratio. The cable should turn 10 revolutions in 52 feet 9 1/2 inches or 100 revs per mile. 100 cable rpms = 60 mph. Joe

1937 Chevrolet Inline-powered Streetrod