The first 5.7 liter third generation Hemi produced up to 350 horsepower at 5,600 rpm and 375 lb-ft of torque at 4,400 rpm — which is one horsepower per cubic inch, just like the Hemis of the 1950s. The second version of the 5.7 Gen 3 rose to 390 horsepower and 407 lb-ft of torque in the Dodge Ram — 375 horsepower in the 2009 Dodge Challenger R/T (with manual transmission) though power varied by the vehicle in which the motor was installed. Now K&N helps give these engines a boost in horsepower thanks to the 71-1542 Blackhawk Induction air intake system.
The generation 3 cast iron block has a hefty deep-skirt design, with a crankshaft supported by four bolts per main bearing (two vertical, two horizontal). The heads are aluminum, while the intake manifold is molded from plastic for reduced weight and increased airflow. The combustion chamber features two spark plugs – just like the top fuel engines based on the gen-2 Hemi.
Chrysler made various revisions to the 5.7L for the 2009 model year. The first for all applications is what Chrysler calls Variable Camshaft Timing or VCT. VCT uses an oil control valve which either advances or retards camshaft timing. Other upgrades include higher compression ratio pistons, cylinder heads that offered better airflow, and an active intake manifold that switches from long runners to short runners by moving a flapper door, emphasizing torque at low engine speeds shifting to delivering horsepower as engine speeds increase.
The Hemi was also available in a 6.1L version for SRT-8 applications. The engine block is different from the 5.7L, with revised coolant channels and oil jets to cool the pistons. A forged crankshaft, lighter pistons, and strengthened connecting rods provide the ability to rev higher and longer. A cast aluminum intake manifold is tuned for high-RPM power and does not include variable-length technology. This engine produces 425 hp at 6200 rpm.
Both the 5.7L and 6.1L Hemi are great engines, however, they are no Hellcat. You can make up a little of the horsepower difference with the 71-1542 K&N Blackhawk performance cold air intake kit. The replacement air induction system boosts horsepower and acceleration to your 5.7L or 6.1L Hemi. In fact, K&N’s own dyno testing has demonstrated an estimated 14.13 hp on a 2014 5.7L Dodge Challenger.
Estimated Horsepower gain- 14.13 HP @ 4188 RPM
CARB EO Number Not legal for sale or use in California