Mountain Motor
A Mountain Motor is an extremely large, high-displacement racing engine used primarily in drag racing, named for its massive physical size that resembles a mountain when installed in a vehicle.
These powerful engines are most commonly seen in a specialized drag racing category called Mountain Motor Pro Stock. Unlike the engines in everyday cars that might have displacements around 200 to 400 cubic inches, Mountain Motors typically range from 820 to 825 cubic inches or even larger. To put that in perspective, that's roughly double the size of most performance car engines.
The nickname "Mountain Motor" comes from the engine's sheer physical size. When mechanics install one of these massive powerplants into a race car, it dominates the engine bay and towers over standard engines, looking almost like a small mountain under the hood. The term has become the standard way racers refer to these oversized big-block engines.
Mountain Motors evolved from the big-block engines of the 1960s, but engineers have continuously modified and enlarged them over the decades. They feature specialized components designed to handle extreme power, including longer crankshafts, heavy-duty connecting rods that measure about 7.750 inches from center to center, and large pistons nearly 5 inches in diameter. The entire engine block stands approximately 12 inches tall from the crankshaft centerline to the top of the deck.
The performance numbers of these engines are staggering. Modern Mountain Motors in Pro Stock racing produce approximately 1,900 horsepower, which is more than ten times the power of a typical family sedan. They run on special racing fuel and operate at compression ratios around 18:1, meaning the air and fuel mixture is squeezed much tighter than in regular engines before ignition.
With this incredible power, Mountain Motor Pro Stock cars can complete a quarter-mile drag race in about 6.25 seconds, reaching speeds close to 225 miles per hour. When these engines first appeared in competition during the late 1970s, they produced around 1,000 horsepower, which was impressive at the time but shows how far the technology has advanced.
The International Hot Rod Association (IHRA) introduced the Mountain Motor Pro Stock class in the late 1970s to make drag racing more exciting and accessible. The cars use similar chassis designs and 5-speed manual transmissions as regular Pro Stock vehicles, but the larger engine displacement creates a different racing experience that requires unique driving skills and engineering expertise.
Today, Mountain Motor racing remains a popular spectator favorite because these engines produce dramatic acceleration and thunderous exhaust notes that showcase the raw power of internal combustion engines at their most extreme.