Nine liters of displacement combined with four overhead camshafts in a V8 configuration means that the Mercury Racing QC4V (quad-cam four-valve) engine pumps out an amazing 1,650 horsepower when combined with a pair of turbochargers and race fuel, and 1,350 horsepower on junky pump fuel.

EngineLabs has discussed this engine program previously, in this article, and today we’re back with an interesting overview of the company’s engine refresh program, which takes place at their Fond du Lac, Wisconsin headquarters — the same place where the engines are initially built. In fact, the refresh program is handled by the same technicians who are responsible for creating the engines in the first place.

The 4.57-inch bores combine with the 4.21-inch crankshaft stroke to product 552 cubic inches of displacement. The engine is optimized to provide a massive torque curve to get a watercraft or automobile up to speed quickly as the engine approaches its horsepower peak.

The refresh program ensures that the engine is back up to snuff with factory specifications; depending upon wear factors and other concerns, the long-block is replaced with either a factory-certified core or a brand-new piece. By the time it leaves the facility, it’s been repainted, dyno-tested, and re-sealed as factory-fresh — with a warranty to boot.

Check out this look at some of the machining processes and people behind the program.