ATK High Performance Chrysler 360 Magnum 320 HP Stage 1 Long Block Crate Engines HP73
$2,435.00
Crate Engine, Mopar 360 Small Block Stage 1, 320 HP, Long Block, External Engine Balance, Magnum Heads, Each
Buy ATK High Performance Chrysler 360 Magnum Online
Upgrade your classic Mopar with the ATK High Performance Chrysler 360 Magnum 320 HP Stage 1 Long Block Crate Engine. Designed for enthusiasts who demand dependable performance and factory-style fitment, this 5.9L (360 CID) crate engine delivers an impressive balance of horsepower, torque, and long-lasting durability. Built with a cast-iron block and Magnum cylinder heads, it features a hydraulic roller camshaft, hypereutectic pistons, and a 9.0:1 compression ratio 360 dodge engine specs for smooth power delivery and reliable street performance.
Whether you’re restoring a Dodge or Chrysler vortec 350 motor muscle car or replacing a worn-out engine, this Stage 1 long block offers a hassle-free solution. Each engine is professionally mn 360 motor assembled and precision-tested to ensure consistent quality and dependable operation. The long block configuration includes the assembled block, cylinder heads, oil pan, valve covers, and timing cover, allowing you to complete your build using your preferred intake, fuel, and ignition components.
The ATK High Performance Chrysler 360 Magnum is an excellent choice for street-driven vehicles, weekend cruisers, and restoration projects where reliability, performance, and value matter most. With 320 horsepower and proven engineering, it provides the chrysler 360 engine confidence and power needed to bring your Mopar back to life.
Product Specifications
| Specification | Details |
|---|---|
| Product Line | ATK High Performance Chrysler Crate Engine |
| Part Number / SKU | HP73 |
| Engine Type | High-performance Mopar small-block Magnum crate engine |
| Displacement | 360 cubic inches / 5.9L |
| Horsepower | 320 HP |
| Torque | 410 ft.-lbs. |
| Block | OE Magnum roller block, 1993–2001 style |
| Bore / Stroke | Up to 4.060 in. x 3.580 in. |
| Crankshaft | OE cast crankshaft |
| Balance | External balance |
| Connecting Rods | OE 6.123 in. rods |
| Pistons | Hypereutectic pistons |
| Compression Ratio | Approximately 9.0:1–9.1:1 |
| Piston Rings | Moly rings |
| Camshaft | Hydraulic roller camshaft |
| Cam Specs | OE Magnum grind |
| Timing Chain | Double roller timing chain |
| Cylinder Heads | OE Magnum cast-iron heads |
| Combustion Chamber | 65cc |
| Valve Size | 1.78 in. intake / 1.50 in. exhaust |
| Rocker Arms | Steel 1.6 pedestal rocker arms |
| Oil Pan | OE front sump, 5-quart style |
| Oil Pump | Melling standard-volume oil pump |
| Recommended Oil | Conventional / non-synthetic 10W-30 |
| Recommended Octane | 89+ octane |
| Recommended Spark Plug Gap | 0.035 in. |
| Firing Order | 1-8-4-3-6-5-7-2 |
| Recommended Timing | 34–36 degrees |
| Recommended Exhaust | 1-5/8 in. headers |
| Recommended Stall Converter | Stock stall converter |
| Quantity | Sold individually |
Key Benefits
Strong Street Performance
With 320 horsepower and 410 ft.-lbs. of torque, the HP73 delivers responsive low- and mid-range power that suits street cruisers, classic Mopar builds, and mild performance applications.
Excellent Drivability
This engine is designed for great street manners, stock-style idle quality, and smooth operation, making it a practical choice for enthusiasts who want added power without sacrificing everyday usability.
Magnum Roller Block Foundation
The OE Magnum roller block provides a proven platform with modern small-block Chrysler design advantages, including hydraulic roller cam compatibility.
Durable Internal Components
Hypereutectic pistons, moly rings, OE-style rods, an OE cast crankshaft, and a double roller timing chain provide a dependable foundation for street performance use.
Torque-Focused Powerband
The 360 cubic-inch displacement and 410 ft.-lbs. torque rating make this engine well suited for heavier classic vehicles, trucks, and street cars that benefit from strong throttle response.
Ready for Custom Completion
As a long block/base engine, the HP73 gives builders flexibility to select the intake, carburetor, ignition, accessories, and exhaust combination that best fits their vehicle and performance goals.
Ideal for Mopar Restorations and Swaps
This engine is a strong option for Chrysler, Dodge, and Plymouth small-block Magnum-based projects where a reliable, performance-oriented replacement engine is desired.
Important Notes
This engine is externally balanced. If using a neutral-balance converter, an externally balanced Magnum 360 flexplate is required. The oil pump does not include an oil pump driveshaft. Component compatibility should be verified before installation, and some vehicle modifications may be required depending on the application.
For emissions compliance, this engine may be restricted to use on uncontrolled, non-emissions-controlled vehicles or closed-course competition vehicles, depending on local regulations.
What vehicles are compatible with the ATK High Performance Chrysler 360 Magnum?
The engine is designed for Chrysler, Dodge, and other Mopar applications that use the 5.9L/360 Magnum platform. Always verify your vehicle’s year, mounting configuration, and accessory compatibility before installation.
What components are included with the ATK High Performance Chrysler 360 Magnum long block?
The long block includes the assembled engine block, Magnum cylinder heads, oil pan, valve covers, and timing cover. Components such as the intake manifold, carburetor, distributor, water pump, and harmonic balancer are typically sold separately.

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