Caterpillar D8
This tractor had the longest production run of the group, with models being built for 33 years from 1941-'74 in Peoria, Illinois. You may see Cat D8s with a bulldozer scoop on the front or a pulling plow like this one had. It's also been used by the military for knocking down trees and scraping fields. This Cat is powered by a 1,246ci (20.4L) six-cylinder diesel engine that's been rated at up to 177 hp (at just 1,200 rpm) and is hooked to a five-speed transmission. It needs that low-speed power to move because it weighs in at a hefty 36,520 pounds that's supported by super-thick leaf springs.
International Harvester 660
This nice two-tone 660 was built back in 1959 and features a vertical L-head oil-burning engine. The 282ci (4.6L) engine was rated at almost 79 hp at the power take-off and was responsible for motivating 7,925 pounds of diesel-powered tractor. Some used gasoline or propane engines that made slightly more horsepower. The transmission has 10 Forward and two Reverse gears. There were 6,945 IH 660 tractors built from 1959-'63 when this model sold for $6,000.