The design was soon bored to and again to , then stroked to , settling on the most common displacement offered until the engine's retirement in 2001, nearly 40 years after the basic block design debuted. Two additional displacements were produced during the engine's history. A model (stroked from the 302) was offered beginning in 1969 and continuing until 1996. The 351W (so identified to distinguish from the 335-series Cleveland 351C) uses a taller block than the other engines in the series to avoid excessively short connecting rods. And for a brief time in the early 1980s a version with a smaller bore diameter that displaced was produced as Ford struggled with emissions and fuel economy.