1989 Mack U-688T – Truck of the Month – May 2024 The introduction of the U series in 1964 surely raised some eyebrows in the industry. With the cab offset eleven inches to the left, the straight on view of the U is certainly Unique. With overall length laws so restrictive, a short bumper-to-back of cab (BBC) was Unbelievably important. Engineering a short BBC truck to accommodate a multitude of engines was a huge Undertaking. With nearly 30,000 U-models produced in its 25-year history, it seems