6 Of The Biggest HEMI Crate Engines Ever Built

Crate engines provide an excellent alternative to rebuilding a stock engine or purchasing a remanufactured long block to renew the HEMI power plant in your Mopar or swap it into your project vehicle. For starters, a HEMI crate engine features all new components instead of reusing items that could be on the verge of failure or have hidden damage to connecting rods, cylinder heads, and exhaust valves.

The other advantage to installing a HEMI crate engine in your favorite Mopar is the ease of upgrading to get the most horsepower from your HEMI engine. HEMI crate engine options range from factory-spec displacements like 6.2L (376 cubic-inch) and 6.4L (392 cubic-inch) versions still available from Mopar Genuine Parts to aftermarket crate HEMI engines with displacements up to 572 cubic inches (9.37 liters).

Considering Stellantis' decision to discontinue the HEMI engine in the near future for cars and pickup trucks, buying a crate HEMI will soon be the only avenue to get a new one. Let's look at the six biggest HEMI crate engines ever built and see what's available today.

[Featured image by Greg Gjerdingen via Wikimedia Commons | Cropped and scaled | CC BY-SA 2.0]

At 376 cubic inches, the 6.2L HEMI is not the biggest or most powerful crate engine ever built. It is, however, readily available from Mopar, made to fit 2015 through 2023 Dodge Challengers, and it's backed by Mopar's transferable nationwide warranty for three years or 100,000 miles.

The 6.2L Supercharged Crate HEMI, part number 68303089AC, uses a 4.090-inch diameter cylinder bore and 3.58 inches of crankshaft stroke to achieve its displacement. Starting with materials like a four-bolt-main cast iron block, forged steel crankshaft, nodular iron camshaft, aluminum HEMI cylinder heads, and forged pistons, the 6.2L HEMI features a 9.5:1 compression ratio and forces more fuel-air mixture into the cylinders with a supercharger induction system.

With a price of $16,827, the 6.2L Crate HEMI includes everything from the water pump to the flywheel mounted clutch assembly and the front sump oil pan to the intake manifold. Power output is rated at 707 hp and 650 lb-ft of torque. If that's not enough, consider Mopar's Hellcrate Redeye 6.2L Supercharged Crate HEMI engine, part number 68303091AC, priced at $22,984.77 with 807 hp and 717 lb-ft of torque, one of the most powerful engines ever put in the Dodge Challenger.

Coming in at just under the 400 cubic-inch mark at 392, the 6.4L SRT Gen 3 HEMI crate engine is another example readily available from Mopar and backed by the same warranty as the 6.2L crate engine above. Its 392 cubic inches come from the cast iron engine block's 4.090-inch diameter cylinder bores and the crankshaft's 3.720-inch stroke.

While not as powerful as the supercharged 6.2L HEMI crate engines, the 6.4L SRT HEMI crate V8 makes a respectable 485 horsepower and 475 lb-ft of torque. On the bright side, it only cost $8,045.

Designed to fit the 2016 Dodge Challenger, the 6.4L SRT HEMI crate engine, part number 68303090AC, is a complete engine assembly. However, installation in your project may require some peripherals, such as a wiring kit, front accessory drive kit, or special SRT exhaust manifolds, all available from Mopar Performance Parts. As always, Mopar warns that its crate engines are not designed as direct replacements and could "require modifications and additional accessories."

The 426 cubic-inch second-generation HEMI wasn't the first HEMI engine, but it undoubtedly changed Chrysler's future. Some vehicles featuring the legendary 426 HEMI engine include muscle car era R/T trimmed Coronets, Challengers, and Chargers from Dodge, the 1971 Plymouth GTX, and most famously the 1971 Plymouth Hemi 'Cuda.

While the original 426 Street HEMI was rated at 425 hp, the newer 426 (7.0L) HEMI crate engines make considerably more power. For example, the Direct Connection 1500 HEMI crate engine, priced at $59,990, is advertised to produce 1,500 hp and 1,000 lb-ft of torque.

There are fundamental differences between the original 426 HEMI and Direct Connection's 7.0L HEMI crate engine. The first 426 HEMI used a 4.25-inch diameter cylinder bore with a 3.75-inch crankshaft stroke compared to the newer crate engine's 4.10-inch bore and 4.05-inch stroke (which calculates to 427.8 cubic inches). The DC 1500 HEMI features premium materials such as billet aluminum pistons, ultra billet steel crankshaft, and a Gen 5 3.0L Stage 2 Whipple Supercharger.

The 472 cubic-inch HEMI based on the second-generation design is currently listed for sale at Year One as part number P5249666 for $23,045.83. Year One specifications for the 472 HEMI crate engine include a heavy-duty cast iron block, cast iron heads, forged pistons, and forged steel crankshaft.

The Year One 472 HEMI crate engine is rated at 525 hp and 540 lb-ft of torque and features a 9.0:1 compression ratio, hydraulic roller camshaft lifters, and valves measuring 2.25 inches for the intake and 1.94 inches for the exhaust. While the crate engine package lacks a carburetor, coil, spark plugs, exhaust manifolds, flywheel, external accessories, and starter motor, it includes nearly everything required to run and an engine stand.

Additional specs from the 2009 Mopar Performance Parts catalog provided by Kolosso Chrysler Jeep Dodge Ram in Appleton, WI include the 427 HEMI's 4.25-inch diameter cylinder bore and 4.150-inch crankshaft stroke. Mopar rated the engine at 530 horsepower.

With its 4.50-inch diameter cylinder bore and 4.150-inch crankshaft stroke, the 528 cubic-inch HEMI crate engine from Ray Barton Racing Engines (RBRE) produces 825 horsepower using readily available pump gasoline, according to a Hot Rod magazine article shared by MotorTrend. However, Hot Rod staff took the RBRE crate engine to the next level to achieve those numbers.

Extra touches included flow testing and touching up the Edelbrock Victor Jr. Gen 2 HEMI cylinder heads, blueprinting the Mopar Performance HEMI engine block, and precisely balancing the rotating assembly for smooth performance. The Hot Rod team installed a single-plane, dual-quad aluminum Edelbrock intake manifold fitted with two 800 CFM Edelbrock AVS carburetors.

On the dyno, the modified 528 cubic-inch HEMI crate engine made 825 hp at 7,000 rpm and 669 lb-ft of torque at 5,800 rpm. All that power and it still fits underneath the hood of a 1965 B-Body Dodge Coronet.

MotorTrend says the largest HEMI crate engine possible is 572 cubic inches due to limitations imposed by the stock camshaft location. The 572 HEMI shares the 528 HEMI's 4.5-inch diameter cylinder bores but increases the crankshaft stroke by 0.400 of an inch to 4.50 inches.

If you're part of the "Bigger is Always Better" crowd, and don't mind spending $28K on an aluminum 572 HEMI long block crate engine, check out what Prestige Motorsports has to offer. PM's 572 Mopar Big Block HEMI Crate Engine, part number M572-SSA-C1 features a reproduction aluminum 426 HEMI engine block bored and stroked to its maximum dimensions and topped with either Edelbrock or Indy Gen 2 aluminum HEMI cylinder heads.

As a long block, the M572-SSA-C1 crate engine doesn't include an intake manifold or ignition system, but it does come with a 7-quart oil pan, black cast aluminum HEMI-logo valve covers, and all the necessary parts in between. Those parts include a solid roller camshaft, forged pistons, and a 4340 forged steel crankshaft. Using PM's specified engine accessories, induction, and exhaust, the 572 HEMI crate engine is guaranteed to produce 700 hp and 650 lb-ft of torque at the flywheel (+/-2%).