Gents,
'47 Merc (early '47) has a 3.78 rear. Routinely have to drive on 65 & 70 mph roads when traveling to events and the original, untouched flathead & drivetrain w/37,000 original miles turns ~3,000 rpm at 60 mph on the speedo (64-65 on a gps - tire size variance). Running with traffic so...