BK-MUNCIE M20*SM C/S*63-65*HD

This part is an internal component for a Muncie M20 wide-ratio 4-speed manual transmission, specifically designed for applications from 1963-1965. The "Sm C/S" likely refers to a small countershaft or a specific configuration for countershafts in this transmission. The 1963 Muncie M20 transmissions featured a small-bore case and a 10-spline input shaft without grooves. Important changes occurred in 1964, affecting the front bearing retainer and bearing bore size. This part caters to the 1963-1965 period, suggesting compatibility with both the unique 1963 configurations and the slightly revised 1964-1965 M20s.