• The Dodge Ram was the only production light-truck with the Cummins 5.9 liter.Martyn Goddard/Photodisc/Getty Images
  
  Dodge Ram pickups have contained Cummins diesel engines since 1989, and continue to feature that brand of engine as of 2010. The 5.9-liter engine, used from 1989 through 2006, was replaced by the 6.7-liter Cummins in 2007. These engines handle heavy loads and significant abuse, just like the trucks in which they were installed.
  
  

Horsepower

• Horsepower reflects an engine's ability to move weight over long distances. From 1989 through 1993, the Cummins engine remained untouched, producing 160 hp at 2,500 revolutions per minute. From 1994 to 2000, engines combined with a manual transmission received a mild boost in power over an automatic transmission, climbing to 235 hp at 2,700 rpm, as opposed to the automatic's 215 hp.
  
  From 2001 through 2004, several 5.9-liters became available each year: California-equipped, base and high-output. From 2001 through 2004, at 2,700 rpm, the CA model produced 235 hp. The HO's production ranged from 245 hp at 2,700 rpm to 325 hp at 2,900 rpm, while the base-model produced 235 hp at 2,700 rpm to 305 hp at 2,900 rpm. In 2005 and 2006, this engine boasted 325 hp at 2,900 rpm.
  
  

Torque

• Torque -- the twisting power produced by the engine -- directly affects the initial acceleration of the vehicle, especially when hauling heavy loads. From 1989 through 1993, the Cummins 5.9-liter engine produced 400 foot-pounds of torque at 1,600 rpm. From 1994 through 1995, it produced 400 foot-pounds at 1,500 rpm with an automatic transmission and 420 foot-pounds with a manual.
  
  The engine boasted a small increase -- to 420 foot-pounds in an automatic transmission and 440 foot-pounds at 1,500 rpm with a manual -- from 1996 through 1997. From 1997 through 2000, it produced 420 foot-pounds in automatic transmission and 460 foot-pounds at 1,600 rpm in a manual. From 2001 through 2003, the base model produced 460 foot-pounds to 555 foot-pounds at 1,400 rpm. The CA model produced 460 foot-pounds at 1,400 rpm, and the HO model produced 505 foot-pounds to 600 foot-pounds at 1,600 rpm.
  
  

Configuration

• All 5.9-liter Cummins engines consist of an inline-six-cylinder (I-6) configuration. The first generation -- 1989 through 1998 -- had 12 valves, or two valves per cylinder in an overhead-valve configuration. The second generation of 5.9 liters, 1998 through 2006, had 24 valves, or four valves per cylinder, in an OHV configuration.
  
  

Internals

• The Cummins 5.9-liter engine didn't see many internal changes through its life. It had a bore, or cylinder width, of 4.02 inches and a stroke -- the piston traveling distance inside the cylinder -- of 4.72 inches. The displacement remained at 359 cubic inches. The one rating that did change was the compression ratio, which represents the highest pressure rating relative to the lowest pressure rating in the combustion chamber. It varied from year-to-year, at 16.3:1, 17:1 or 17.2:1.