How Much Horsepower A Proline Hemi Engine Produces (And What It Costs)

Hemispherical ("hemi") engines have been around since the early years of the 20th century, although they didn't become common in the auto industry until Chrysler started dropping its 331 cubic inch "FirePower" V8 in cars in 1951 (which is also when Chrysler began using the HEMI brand name). Hemi engines really took off when a 426-inch version appeared in the Plymouth Belvedere in 1964, helping Plymouth take all three podium spots at that year's Daytona 500. The street version of the 426 was in production through 1971, and it made the design famous. 

Hemi engines are named for the domed shape of the combustion chambers, which allows for a more concentrated transfer of power to the pistons. The hemi design also allows for bigger valves to be mounted at an angle, allowing for better flow of the fuel/air mixture and exhaust gases. Hemi engines are bigger and heavier than other designs, although for many applications this is mitigated by the additional power they provide. One such use is in racing, where engine bays can be modified to accept larger engines and power output is of utmost importance.

Proline Racing was founded by Eric Dillard and Doug Patton in 2005, when they took over the foundering Atlanta-area shop where they both worked. They have since built Proline into a global enterprise that has built engines for National Hot Rod Association and World Street Nationals champions, and their current product line includes hemi engines that are suitable for track or dragstrip use. But how powerful are Proline's hemi engines, and how much do they cost?  

While a typical sporty commuter car like the 2024 Volkswagen Jetta GLI has a turbocharged four-cylinder engine that produces 228 horsepower, the Proline Racing raised-cam hemi can make more than 5,000 horsepower when supplemented with available turbochargers. That's about five times as powerful as the Chevy Performance 632/1000 engine that powers the 2023 COPO Camaro. As you might imagine, 5,000 horses don't come cheaply. The Proline 564 cubic inch raised cam, raised port engine shows above is listed on Proline's website for $82,500. 

For that massive pile of nickels you get a freshly rebuilt engine with new pistons and rings, connecting rods, and titanium valves, plus a new wet sump oiling system. Proline will also throw in 16 FuelTech 720 pound per hour injectors and two 105 millimeter throttle bodies with a Y adapter to mount them. If you're not prepared to spend quite that much on a racing engine, Proline once listed a used 548 cubic inch hemi available for $49,900.