• Thinkstock Images/Comstock/Getty Images
  
  The name Hemi has been synonymous with performance on Dodge vehicles for almost 40 years; however, only recently did the 5.7 liter version become available. In 2005, Dodge included a 5.7 Hemi in 45 percent of its trucks. The performance, as well as cost effectiveness of the engine, has made it one of the most successful engines that Dodge offers.
  
  

Generations

• The 5.7 liter Hemi has been developed in two forms since it jumped on the market. The first is called the "first generation 5.7 liter Hemi." At 5,600 revolutions per minute, it produces a total of 345 horsepower. It also includes 375 pound-feet of torque at 4,400 rpm. The "second generation 5.7 liter Hemi" is a more powerful and newer version of the engine. It has only been available since 2009 and was included within not only the 2009 Dodge Ram 1500, but also in the 2009 Dodge Challenger. The engine has variable cam timing and closes the four cylinders frequently to achieve better fuel efficiency. The second generation 5.7 liter Hemi produces 390 horsepower and 407 pound-feet of torque.
  
  

MDS

• The hemi 5.7 comes equipped with an MDS---or Multi Displacement System---which shuts down fuel flow within four cylinders when it is unnecessary to have fuel in those locations. According to Chrysler, MDS system usage has saved over 100 million gallons of gasoline over the years of its usage (2005-2009). It also has reduced carbon dioxide emissions, estimated close to a million tons less than what was produced by alternative engines.
  
  

Features

• The 5.7 Hemi cam is high on the block, keeping the pushroads short, it also has oversized lobes and journals, which lessen the stress on the lifters. The valve springs are lighter than traditional springs used in other 5.7 engines. The entire engine is designed as a light weight engine, using precision cast technology. To offset the weight of the larger counterweights installed in the crank, the 5.7 Hemi utilizes lightweight rods and pistons. The total power of the Hemi is 41 percent more than alternative 5.7 liter engines.