In the latest years the concern for lower drag coefficients and aerodynamic shapes has started to receive more attention than ever and given the continuously rising fuel costs there is no wonder why.

One of the most aerodynamic trucks from the road is the Kenworth T660 which was designed with a slippery shape that defies the air and offers a better fuel economy.
The Kenworth T660 is available with both single and sleeper cabs and is equipped with a range of capable MX engines which develop between 380 – 485 hp.

  • 2008 Kenworth T660
  • Year:
  • Make:
  • Horsepower @ RPM:
    485 @ 1600
  • Torque @ RPM:
    1650 @ 1100
  • Top Speed:
    80 mph
  • Price:


2008 Kenworth T660 Exterior
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Kenworth has continuously tested the T660 in the wind tunnel, until it achieved one of the most aerodynamic trucks that run on today’s roads. Every part of the truck received maximum attention from Kenworth’s engineers and was designed to keep the drag coefficient to as low as possible. The slippery shape is further enhanced by the raked hood which is combined with a curved windshield and aerodynamic bumper and fairings.

The front features the typical Kenworth grille split in two sections by a central vertical stripe and surrounded by a nice chromed border. The air that passes through the grille is directed to the engine keeping it cool, while the air routed through hood inlets flows directly to the air cleaner and climate control system.

The sleek light-clusters gel well with the slippery shape of the truck and are equipped standard halogen lamps which produce 44% more light output than a conventional sealed beam lamp. Moreover, the truck is also available with optional Xenon HID headlights.

Kenworth’s conventional cab combines aluminum and fiberglass construction and uses aircraft-grade huck-bolts, to be corrosions resistant and rattle-free.


2008 Kenworth T660 Interior
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Hop inside and you’ll find a pretty relaxing place to be in, with plenty of space and a good overall ergonomy. One common complaint about the Kenworth T660 has been interior cheapness, as the materials aren’t as good as the ones from Mack or Volvo. The fittings and the build quality are also surprisingly poor compared to rivals; hence those that check the dashboard’s contours with finger prods and knuckle rapping will be heavily disappointed. On the other hand, we like the optional deeply tufted interior which is available for the superior trim levels.

The curved dashboard is fitted with a bunch of switches, gauges and controls which have a pretty intuitive layout and are easy to reach. The instrument cluster gauges light up a nice soft blue that is not disturbing for the eye and makes them easy to read. There is also an information display mounted in the middle of the instrument cluster which is lighted by a bright green color but it looks a bit out of place compared with the rest of the indicators.

Poorly padded and devoid of much bolstering, the Kenworth T660 seats won’t be mistaken for anything sporty, but luckily, long trips won’t make you fidgety, as the wide range of adjustments available will help you to find a good driving position. The seats are also fitted with convenient armrests which fold out of the way if needed.

The Kenworth steering wheel isn’t our first choice when it comes to design, but we’ll have to admit that it feels good to hold and can be easy adjusted for reach and rake.

Unsurprisingly, the high driving position, the huge two piece windshield and the plate sized door mirrors translate into an excellent all-round visibility.

The aero cabs offer acres of space and are fitted with big and comfortable beds, and numerous storage places to make your life on board easier. Kenworth offers up to six different configurations for its sleeper aero cabs which come with or without high roofs.

Engines and performance

2008 Kenworth T660 Exterior Drivetrain
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As most trucks built by Kenworth, the T660 is also offered with a choice of torquey Paccar MX engines which boost between 380 – 485 hp with very generous torque figures that can go up to 1650 lb ft.

The engines are bolted on the Eaton UltraShift PLUS automated transmission which was designed to offer relatively low fuel consumption and maximum performances. To further improve the fuel consumption the Paccar MX series also comes with an integrated Electronic Control Module system and individual injection pumps.

The engine’s cylinder block and head are made of compacted graphite iron which is both lightweight and ultra strong further improving the engine performances.

To extend the service intervals, the integrated lubrication module of the MX combines filters, a thermostat and an oil cooler joined directly to the engine without external lines.

Kenworth T660 engines specifications

ENgine hp@rpm lb-ft@rpm
Paccar MX 380 @1600 1,450 @1100
Paccar MX 405 @1600 1,450@1100
Paccar MX 430 @1600 1,550@1100
Paccar MX 455 @1600 1,650@1100
Paccar MX 485@1600 1,650@1100

Ride and suspensions

2008 Kenworth T660 Exterior
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The truck’s frame is a continuous straight rail constructed of heat-treated steel for superior strength, custom drilled according to specific needs. For a better strength the gussets and crossmembers are free-fit fastened while the air and light lines are mounted high on the frame with chafe-resistant clips.

The Front axles can deal with 12,000 to 14,600 lb of weight, while the rear axles have a capacity between 23,000-lb to 46,000-lb. For a better maneuverability the Kenworth T660 is equipped with a set-back front axle which offers a generous wheel cut and also a better weight distribution.

The air suspended cab and the 64-inch taper leaf springs offer a fairly smooth ride which keeps most of the road bumps away from the driver’s seat.


In the end, the T660 does what it was designed for and that’s transporting massive payloads with the fuel consumption kept to as low as possible. In order to stay true to the company’s core values, the truck had to prioritize its aerodynamic abilities and whether you like its looks or not you’ll definitely love its low drag coefficient.

The Kenworth T660 puts up solid numbers and has got the goods where it counts, with strong engines and solid axles. The long lasting anticorrosive aluminum cab is fairly comfortable and despite its cheap plastics and the relatively poor built quality, it has good ergonomics and an excellent all-round visibility, while the sleeper cab offers acres of space and comfortable beds.

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