The last year for Muncies to be installed in PRODUCTION GM cars was 1974.
In the 75-later GM models, the 4sp was a Borg-Warner which was based on the 57-63 B-W T-10. The 75-later T-10s were beefier, had thicker gears and a higher nickel content. They had the 26spline input shaft and the larger 32spline tailshaft. So, beginning with the 75 T-10 versions, they became known as SUPER T-10s. As a result, the Super T-10s were nearly equivalent in strength as the earlier Muncies. Thus, a Super T-10 in good, or properly rebuilt, condition is an excellent tranny.
Sometime in the LATE 80s or EARLY 90s, Richmond bought the B-W T-10 design and now the Richmond Super T-10 is simply the old B-W ST-10 tranny.
Sooooooooooo, how do you tell if a Super T-10 is a B-W or Richmond built tranny. You gotta look at the raised casting logos on the case.
Also, does someone here know the exact date, or close approximate date, when the Super T-10 changed from B-W manufacture to Richmond manufacture? As I understand it, the change occured at about the same time the Doug-Nash 5sp was bought out by Richmond and became the Richmond 5sp.