 The unit features a 20mm x 17 spline input shaft, uses a rod-based shift linkage and was originally only available in 4-speed format, designated as BC4, and designed to mate either with the Valencia version of the OHV Ford Kent engine, or the CVH unit.The 5-speed BC5 version appeared in 1982 on the Escort as a standard fitment on 1.6 litre cars, and as an option on 1.3 models.A completely revised version of the transaxle was introduced in 1995 and was designated iB5, and was initially introduced for the Mk.4 Fiesta.