1940-1945 - During the war years, Mack built heavy-duty trucks to support the Allied forces. And, just like other companies, Mack had its own version of "Rosie the Riveter" to help in the effort! Mack was a major military contractor on a much larger scale in World War II, with more specialized products. Mack trucks served the Allied forces 35,000 strong in that second conflict, in the form of prime movers, personnel carriers, wrecker trucks, tank transporters, and more. 1940-1953 - Mack produced marine engines for many years. "The Mariner" engines were used in yachts, pilot and work boats. The ENDM 405 (FW) was produced from 1940-1941; a total of 16 engines were manufactured.