BORG WARNER TRANSMISSIONS, known for their smooth, Velvet Drive, have been the industry standard for decades. The 71C and 72C designations indicate input horsepower ranges. Typically, a 71C is found on small blocks and a 72C is used on big block applications. The most popular model is the in-line unit. In-line indicates that the input and output shafts of the transmission are on the same axis. Direct Drive (1:1) versions of the in-line models are frequently used on high horsepower, lightweight boats. The reduction ratio versions (1.5:1) use an additional planetary gear set to allow the use of larger propellers for greater pulling power at lower shaft speeds, often found on Mastercrafts.