Introduced in the 1980s, the 637E combined speed and mobility with substantial earth-moving prowess. These units handled large capacities of topsoil more effectively than bulldozers, and over larger distances. The 637E came standard with a four-stroke 3408 turbocharged V-8 engine which generated 450 flywheel horsepower and rear 6-cylinder, 250 horsepower 3306. These included direct-injection CAT fuel systems with individual, adjustment-free injection pumps, variable injection timing and water jacket aftercooling. A 24-volt electric starting system with an ether starting aid was included for use in cold temperatures. An electric monitoring system oversaw critical functions of engine operation. Tractor and scraper together weighed 113,500 pounds when empty, but over 190,500 pounds when its 75,000 (~31 cubic yds) capacity load was maxed. The scraper could cut as deep as 17.2” with a blade width of nearly 11.5’.