The AMC Model 20 is an automotive axle manufactured by American Motors and AM General.
AMC 20s have an 8 7/8" ring gear and use a 29 spline axle shaft.
The AMC 20 was most often used with V8 engines in cars and Jeeps.
[1] Letter codes were stamped on the axle to indicate installed gears.
AMC changed or reused letter codes during the axle's long life.