The present invention has apparatus converting a Ford Mustang five-speed transmission for installation in other, substantially different, automobiles by having a clutch housing, adapted to fit the front face of the Ford Mustang case, with gearing for four forward speeds and has an externally splined output shaft extending 5 inches beyond the rear face of the case; an output shaft housing, also housing a set of fifth-speed gears, the speedometer drive gearing and a gear shift lever gate within a dimension of approximately 3½ inches, to provide an overall length of approximately 20½″, as measured from the engine mounting surface of the clutch housing to the rear face of the drive shaft connecting flange.