Muncie 4-Speed Casting Numbers

Main Case

38317041963 Only small 6207NR Front Bearing ,Pat. Pending, 7/8" Bore
38396061963 - 1964 Regular Bearing Pat. Pending, 7/8" Bore
3864_____1964 Milled off last 3 digits 7/8" Bore Patent Pending
38513251964 - 1965 7/8" Bore Patent Pending Mostly 1964
38513251964 - 1965 7/8" Bore Patent Number
3885010 1966 - 1967 1" Bore Patent Number
39256601968 - 1970 1" Bore Patent Number
3925661 1970 - 1974 (some early 1975 cars) 1" Bore Patent Number

Tail Housing

38317311963 "Thin Fin Tail" Driver speedometer 27 spline
38464291963 "Thin Fin Tail" Driver speedometer 27 spline
38464291963 - 1965 Regular thick web, driver speedometer, 27 spline
9779246 1964 - 1965 Pontiac Catalina Long Tail Driver Speedo 27 Spline
3857584 1966 - 1970 Passenger side speedometer, 27 spline
3978764 1970 - 1974 passenger speedometer, 32 spline output

Side Cover

38317071963-1965 Early side cover stud type shift shafts
3884685Cover issued with "584" tail stud type shift shafts
3950306Short boss with bolt on type shift shafts - no switches
3952642Long boss bolt on type w/ TCS switch on 3-4
3952648Short boss bolt on type w/ TCS switch on 3-4
335308Long boss bolt on type with neutral safety switch. Some have a boss for the switch that is cast but not machined on 1-2.

Ref: http://www.5speeds.com/casting.html