Tom,
My Series 6 Minx automatic had 3.89 axle gears. I have only seen the 3.7
used on the fastback Alpine (Rapier) cars, with automatic transmissions.
Other Rootes ratios are as follow: 5.22:1 4.778:1 4.55:1 4.44:1
Early cars used spiral-bevel gearsets, which are not as strong as the
later hypoid gears. The Hypoid pinion gear addresses the crown gear below the
centerline, allowing a greater contact surface area. Pinion gear tooth count
is different, as well as the axle cases. What are you looking for. Freeway
gearing or stump pulling ratios?
Jim Leach PTC Seattle
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