Rear Axle - 7 1/4 or 8 1/4

Model 7 1/4
Ring Gear Diameter, Inch 7 1/4
Gear Ratios [01] 3.55 or 3.90

Model 8 1/4
Ring Gear Diameter, Inch 8 1/4
Gear Ratios [01] 3.21, 3.55 or 3.90

Footnote:

[01] -- Stamped on differential housing tag.