The reference that I got from this forum shows WFV as 2.75:1 ratio, however WFV is the axle model and the tag should tell it all. Also wheel flange to wheel flange is 58 1/2" for 77-81 Versailles or 58" on another chart.

WFV = Axle model
7LC = Plant Code
2 L 50 = 2.50 ratio with Traction Lok
9 469A = Date code (year/ month/ week)???????????? I don't understand this date code. Anyone?