Repair, Once you get used to it, you will be able to shift by ear and not need the tach. I had a tach in mine and hardly ever looked at it. One thing tho, altho many don't drive this way no more, I always use the clutch and I always double clutch. Mine had a 10 Speed Road Ranger tho. A 5 Speed is actually easier to drive. A 2 Speed Rear needs some getting used to if you split shift all the gears. A 6-71, like all Detroits are high revers, but I don't like to over rev them, even tho they have governors.