The Borg Warner T-10 cast-iron case four-speed was introduced in 1957. Until late 1963, T-10s had a cast-iron housing, 10-spline input, and 16-spline output-shaft with an overall length of 21.5 inches and 14 inches from case to mount. These boxes disappeared from Chevrolet production cars until its triumphant return in 1974. Renamed the Super T-10, or Second Design, the new trans featured a 22.25-inch overall case length and kept the 14-inch trans mount location but switched to an aluminum case. The splines followed Muncie’s lead and picked up the 26/32 input/output shaft configurations.

The Super T-10 has a Borg-Warner stamp and all factory Super T-10s have aluminum main cases. The T-10 will need a 16-spline slip-yolk to work in the Chevelle; the overall dimensions are that of the pre-’71 M20 and M21, and the pre-’70 M22. The Super T-10 needs a 32-spline output shaft to work; it has the same dimensions as the ’71-and-later M20 and M21, and the ’70-and-later M22.

Richmond Gear also offers an updated version of the Super T-10 four-speed; it weighs in at a slight 70 pounds, will tolerate up to 375 ft-lbs of torque, and has an overall length of 22.61. If this trans is used as a replacement for the Powerglide, a 32-spline yolk will have to be used and the driveshaft will have to be shortened 1-½ inches. The Richmond uses the same 14-inch mount location.