The Saginaw was used in low horsepower spec applications. They're not the most durable of the four speeds, but are OK if you don't ask more of them than was intended. Just tooling around town? I wouldn't hesitate to use one. As for being a close cousin to the Muncie? Not really. The Saginaw four speed was developed from the three speed version by narrowing the internals and cramming in the fourth gear. The Muncie was designed from the ground up as a four speed, and unlike the Saginaw, has reverse in the tailshaft to leave lots of room in the maincase for gear width.

Bob