Mack Trucks in military service, that are shipped partially knocked down, differ mainly in the body structure.
5-ton 4x4 ponton semi-tractor Closed van (8) 5-ton 6x4 Closed and open cab Commercial 4x2 COE, semi-tractor, open cab Heavy duty 4x2 Cargo, dump, van, tank, off-road 5-ton 6x6 cargo truck Dump, wrecker, tractor, and others 10-ton 6x4 Cargo truck Closed and open cab 7 2-ton 6x6 6-ton 6x6 Prime-mover 8-ton 6x6 truck Dump, flatbed, and others Commercial 6x4 Semi-tractor, tanker 10-ton 6x6 truck Semi-tractor, prime-mover It had a 471 cu in (7.7 L) L-head inline 4 cylinder gasoline engine developing 40 hp (30 kW). It had a 706 cu in (11.6 L) L-head inline 6 cylinder developing 150 hp (110 kW) at 2000 rpm. Early models had an EN310 310 cu in (5.1 L) L-head inline 6 cylinder gasoline engine developing 90 hp (67 kW). Their EP 611 cu in (10.0 L) gasoline OHV I6 developed 160 hp (119 kW). Their 532 cu in (8.7 L) L-head inline 6 cylinder gasoline engine developed 136 hp (101 kW) at 2400 rpm. Their EY 707 cu in (11.6 L) overhead valve inline 6 cylinder gasoline engine developed 170 hp (130 kW). They used the same EY 707 cu in (11.6 L) overhead valve inline 6 cylinder gasoline engine developing 170 hp (130 kW) as the NM series. An ED 519 cu in (8.5 L) inline 6 cylinder diesel engine developed 131 hp (98 kW). Continental 6606 602 cu in (9.9 L) overhead valve inline 6 cylinder gasoline engine developing 224 hp (167 kW) at 2800 rpm was used. A LeRoi T-H844 844 cu in (13.8 L) overhead valve V8 cylinder gasoline engine developed 297 hp (221 kW) at 2600 rpm. A mid-range Caterpillar 3208 636 cu in (10.4 L) V8 diesel engine developed 225 hp (168 kW) at 2,800rpm. An EM6 Maxidyne 673 cu in (11.0 L) turbocharged inline 6 cylinder diesel developed 285 hp (213 kW) at 1,800rpm. An ENDT673 673 cu in (11.0 L) turbocharged inline 6-cylinder diesel developed 225 hp (168 kW) at 2,100rpm. A MP8 13-Liter turbocharged inline 6 diesel develops 400 hp (300 kW) and 1,460 lbfft (1,979 Nm). A turbocharged inline 4 diesel engine develops 215 hp (160 kW) at 2300 rpm and 590 lbfft (800 Nm) of torque at 1200 - 1700 rpm. 
