Value? My Father-in-laws 1971 Cutlass Supreme Convertible

[njsteve]

And I drained the rear differential, pulled the cover and wiped out any remaining old fluid. It was black and yucky but no metal and the magnetic pipe plug was clean. New gasket and new 75w90 back in.

Am I reading the gear set right at 2.56? It does say 41-16 and if my math skills are still at middle school level, that comes out to 2.5625 to 1. That would explain the 2 to 3 shift point at 50 mph!