Description
ATK High Performance Chrysler 5.7L Gen III HEMI Crate Engine – 400 HP | HP103T
Unlock the legendary power of a modern HEMI for your project. The ATK HP103T is a high-performance, remanufactured 5.7L Gen III HEMI long block crate engine built to deliver over 400 horsepower, offering an exceptional balance of street performance, reliability, and value. This engine is the ideal foundation for anyone looking to upgrade a modern Mopar vehicle or inject classic muscle cars, trucks, and Jeeps with state-of-the-art power.
Collaboratively engineered with Comp Cams, this HEMI is equipped with a performance hydraulic roller camshaft and eliminates the complex Multi-Displacement System (MDS), simplifying swaps and enhancing durability for performance applications. The build features key upgrades including billet full roller rockers, hypereutectic pistons, and a reconditioned valvetrain, all precision-assembled to ensure robust power delivery.
Sold as a complete long block, the HP103T provides the flexibility to customize your intake, exhaust, and accessory drive to perfectly suit your vehicle’s needs. Whether you’re modernizing a classic Mopar, boosting your Ram 1500, or executing a groundbreaking Jeep swap, this ATK HEMI provides a turn-key engine core that’s dyno-ready and built to perform.
Technical Specifications
| Specification Category | Detail |
|---|---|
| Manufacturer Part Number | HP103T |
| Engine Type | Chrysler Gen III HEMI |
| Displacement | 5.7L / 345 cu. in. |
| Max Horsepower (HP) | 400+ HP (Estimated) |
| Compression Ratio | 9.6:1 |
| Engine Block | Remanufactured OEM Cast Iron Block |
| Crankshaft | OEM Reground & Micro-Polished |
| Connecting Rods | OEM Reconditioned |
| Pistons | Hypereutectic with Chromoly Rings |
| Cylinder Head Material | Aluminum |
| Valvetrain | Billet Full Roller Rockers, Upgraded Pushrods & Springs |
| Camshaft Type | Hydraulic Roller (Non-MDS) |
| Balance | Internal |
| Assembly Level | Long Block |
What’s Included (Long Block)
| Included | Not Included / Required Separately |
|---|---|
| ✓ Remanufactured & Assembled Short Block | ✗ Intake Manifold |
| ✓ Aluminum Cylinder Heads w/ Roller Rockers | ✗ Oil Pan, Pickup Tube, & Timing Cover |
| ✓ Hydraulic Roller Camshaft (Non-MDS) | ✗ Front Accessory Drive (Balancer, Water Pump) |
| ✓ Upgraded Valvetrain Components | ✗ Flexplate / Flywheel |
| ✓ Valve Covers (Note: May vary) | ✗ Ignition System (ECU, Harness, Coils, Plugs) |
| ✗ Exhaust Manifolds / Headers |
Comparison Table: ATK HP103T vs. Alternatives
| Feature | ATK HP103T 5.7L HEMI | OEM Stock 5.7L HEMI | BluePrint 5.7L HEMI (New Build) |
|---|---|---|---|
| Power Output | 400+ HP (Performance Cam, No MDS) | ~350 HP (Includes MDS) | Varies (Often 350-400HP) |
| Key Differentiator | Performance Cam & Valvetrain, No MDS | OEM Spec, Full MDS Functionality | All-New Components |
| Block Core | Remanufactured OEM Casting | New or Remanufactured OEM | New Aftermarket Casting |
| Ideal For | Swaps, Restomods, Performance Upgrades | Direct OEM Replacement | Restomods, New Builds |
| Complexity | Simplified (MDS Deleted) | Complex (MDS Active) | Simplified (Typically No MDS) |
| Value Proposition | High Performance on an OEM Core | OEM Reliability & Emissions Compliance | New Component Warranty & Precision |
Frequently Asked Questions (FAQs)
Q1: What does “Non-MDS” mean and why is it beneficial?
A: MDS (Multiple Displacement System) is Chrysler’s cylinder deactivation technology. It uses specialized lifters and a complex control system to switch between 4 and 8 cylinders. The ATK HP103T deletes this system by using a standard hydraulic roller cam and non-MDS lifters. This simplifies the engine, eliminates a potential failure point, and makes it vastly easier to wire and tune for engine swaps, as it doesn’t require the OEM body control modules.
Q2: Will this engine work in my Jeep Wrangler TJ/JK or classic car swap?
A: Yes, it is an excellent candidate. The removal of MDS makes it one of the most popular choices for swaps. You will need a complete HEMI swap kit that includes custom engine mounts, headers, an oil pan designed for your chassis, and a standalone wiring harness and ECU (like from Hotwire Auto or similar) to make it run.
Q3: Is this a complete, ready-to-run engine?
A: No. This is a long block. It includes the engine block, cylinder heads, camshaft, and internal components. You must source and install all external components: intake manifold, throttle body, oil pan, front accessories, ignition system (coils, plugs, wires), and engine management (ECU and harness).
Q4: Can I use my stock intake, exhaust, and accessories from my Ram 1500?
A: For a direct replacement in a vehicle that originally had a 5.7L HEMI, yes, your stock accessories, intake, and exhaust manifolds will physically bolt on. However, the performance cam will require a custom tune for the engine to run correctly, even with all the stock components.
Q5: What kind of warranty does this engine have?
A: ATK Engines typically come with a robust limited warranty. Please confirm the specific terms with your authorized dealer at the time of purchase, but industry standard is often 3 years/unlimited miles for remanufactured performance engines.
Pros and Cons
| Pros | Cons |
|---|---|
| Significant Power Gain: 400+ HP output overrules stock HEMI models. | Long Block Only: Requires significant additional parts investment for a complete running engine. |
| Simplified for Swaps: Elimination of MDS drastically reduces wiring and tuning complexity. | Remanufactured Core: Built on a used OEM block, not a brand-new casting. |
| Performance Upgrades Included: Features Comp Cams camshaft and roller rockers out of the box. | Requires Custom Tuning: Will not run properly with a stock ECU calibration. |
| Proven HEMI Architecture: Leverages the renowned reliability and torque of the 5.7L HEMI design. | Not Emissions Legal: For off-road/racing use only due to changes in cam and deletion of emissions equipment (MDS). |
| Excellent Value: Offers a high-horsepower starting point for a fraction of the cost of a full custom build. |
Conclusion & Ideal Use Case
The ATK HP103T 5.7L HEMI is the ultimate power plant for the enthusiast who wants modern Mopar performance without modern electronic complexities. It is engineered for those who prioritize power and simplicity for a project build.
This engine is perfectly suited for:
-
Classic Mopar Restomods (Charger, Challenger, Cuda)
-
Jeep Wrangler & Grand Cherokee HEMI Swaps
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Performance Upgrades for 2003-2008 Ram 1500s, Durangos, and other non-MDS vehicles
-
Custom Hot Rods and Kit Cars needing a reliable, torque-rich V8
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Anyone looking for a simplified, high-output Gen III HEMI foundation.
If your goal is a straightforward, powerful, and tuner-friendly HEMI swap that captures the modern muscle spirit, the ATK HP103T is a formidable and smart choice.
