Engineers put a lot of effort into making the 2006 Cadillac STS-V worthy of its V-series designation, though at the heart of it all is a superb supercharged engine. The 4.4-liter, 32-valve, dual overhead cam, Northstar V8 with variable valve timing cranks out 469 horsepower at 6,400 rpm and 439 lb.-ft. of torque at 3,900 rpm, with peak twist available between 2,500 and 6,400 rpm. Based on the popular 4.6-liter V8 currently used throughout much of the Cadillac lineup, the 4.4-liter motor incorporates the use of new heads, crankshaft, pistons, and connecting rods, a multi-layer steel head gasket, twin induction silencers designed to limit supercharger whine, and a Roots type supercharger offering 10-12 psi. Each engine is hand-built in Michigan, and ultimately connects to a six-speed, manually-interactive automatic transmission.