eliminating the A-body axle assemblies

1970 E-Body:
the "048" is a 741 w/2.76 ratio OPEN & 10" brakes
the "100" is a 741 w/3.23 ratio OPEN & 10" brakes
the "341" is a 741 w/3.23 ratio OPEN & 11" brakes

the "049" is a 489 w/3.23 ratio OPEN & 10" brakes
the "073" is a 489 w/3.23 ratio OPEN & 11" brakes

there are a number (for use in "axle packages") that do not have an "*" for sure-grip

anyone know what the "S" & "L" represent by the pinion diameter?