Creating the 6.1-liter Hemi found in the 2006 Jeep Grand Cherokee SRT-8 required a bit of engineering work. To create additional displacement and horsepower, the cylinders were bored out by 3.5mm, compression was raised from 9.6:1 to 10.3:1, and engine breathing was improved through the use of high-flow heads and intake, fresh air induction, and performance-oriented camshaft profiles. Exhaust headers with individual tubes encased in stainless steel route spent gases through four-inch chrome exhaust tips. The Hemi engine is also strengthened with a forged steel crankshaft, high-strength powdered-metal connecting rods, floating pin pistons, and an oil pan designed to improve flow at high engine speeds.