 A total of 3,945 SD40-2 units were built.EMD introduced their new 710 engine in 1984 with the 60 Series locomotives (EMD SD60 and EMD GP60), the EMD 645 engine continued to be offered in certain models (such as the 50 Series) until 1988.The 710 is produced as an eight-, twelve-, sixteen-, and twenty-cylinder engine for locomotive, marine and stationary applications.