Muncie m21 4 speed transmission close ratio. Has 7/8” cluster pin 10 spline input shaft with one groove. 27 spline output shaft. Gears look good inside no chipped gears. I do not know the history of this trans. I bought it for a project car and sold the car before installing it. Main case number is 3885010 Shift cover number 3884685 Tail case number 3857584. Case is in good shape no broken tabs.