Description
ATK High Performance Chevy 383 Stroker Crate Engine – 470 HP | HP101M
Unleash raw, untamed power with the ATK HP101M—a 383 cubic inch Chevy stroker crate engine built to dominate both the street and the strip. This isn’t just an engine; it’s a statement, producing a massive 470 horsepower and 490 lb-ft of torque with a aggressive demeanor and a soundtrack to match. Designed for the enthusiast who refuses to compromise, this mid-dress long block comes loaded with premium components right out of the box, minimizing the parts you need to source and maximizing the fun.
Built on a seasoned GM 4-bolt main block, this stroker combines a SCAT forged rotating assembly with proven performance parts like Dart SHP aluminum heads, a hydraulic roller cam, and a Weiand Stealth dual-plane intake. The “mid-dress” configuration is its key advantage, including critical components like an MSD HEI distributor, harmonic balancer, water pump, and valve covers, saving you significant time and money.
Be advised: this engine is built for performance, not practicality. Its aggressive cam profile means it will not produce sufficient vacuum for power brakes and requires a high-stall torque converter (2,500 RPM+) for automatic transmissions. If your goal is a brutal, high-revving small block that makes its presence known, the ATK HP101M delivers turn-key fury.
Technical Specifications
| Specification Category | Detail |
|---|---|
| Manufacturer Part Number | HP101M |
| Engine Type | Chevrolet Small Block V8 Stroker |
| Displacement | 383 cu. in. / 6.3L |
| Max Horsepower (HP) | 470 HP @ 5,200 RPM |
| Max Torque (lb-ft) | 490 lb-ft @ 4,800 RPM |
| Compression Ratio | 10.0:1 |
| Engine Block | Seasoned GM Cast Iron (4-Bolt Main) |
| Crankshaft | SCAT Nodular Iron |
| Connecting Rods | SCAT 4340 Forged I-Beam w/ ARP Bolts |
| Pistons | Forged |
| Cylinder Head Material | Aluminum (Dart SHP, 72cc Chamber) |
| Valve Size | 2.02″ Intake / 1.60″ Exhaust |
| Valvetrain | Billet 1.6 Ratio Aluminum Roller Rockers |
| Camshaft Type | Hydraulic Roller |
| Camshaft Specs | 224°/236° Duration @ .050″, .591″/.591″ Lift, 108° LSA |
| Fuel Requirement | 91 Octane (Premium) or Higher |
| Oil Recommendation | 10W-30 |
| Rear Main Seal | 1-Piece |
What’s Included (Mid-Dress Long Block)
| Included | Not Included / Required Separately |
|---|---|
| ✓ Fully Assembled Long Block | ✗ Carburetor |
| ✓ Weiand Stealth Dual-Plane Intake Manifold | ✗ Spark Plugs & Wires |
| ✓ MSD GM HEI Distributor | ✗ Flexplate / Flywheel |
| ✓ Aluminum Valve Covers | ✗ Air Cleaner |
| ✓ Harmonic Balancer (Internal Balance) | �Fuel Pump |
| ✓ Water Pump (Long Style) | |
| ✓ Timing Cover | |
| ✓ Oil Pan (5-Quart OEM Style) |
Comparison Table: ATK HP101M vs. Alternatives
| Feature | ATK HP101M 383 Stroker | Mild Street 383 Crate Engine | DIY 383 Build |
|---|---|---|---|
| Power Output | 470 HP / 490 lb-ft (Aggressive) | ~400-430 HP / 450 lb-ft | Unknown (Risk of Imbalance) |
| Camshaft Profile | Aggressive Hyd. Roller (108 LSA) | Mild Hyd. Roller (112+ LSA) | Varies |
| Vacuum Production | Very Low (Not for Power Brakes) | Good (Supports Power Brakes) | Varies |
| Configuration | Mid-Dress (Includes Intake, Dist., WP) | Often Long Block Only | Self-Sourced |
| Ideal Use | Street/Strip, Race Applications, Hot Rods | Cruising, Daily Driving, Restomods | For Experienced Builders Only |
| Value Proposition | High Power with Key Components Included | Drivability and Comfort | Lowest Cost, Highest Risk |
Frequently Asked Questions (FAQs)
Q1: The notes say it won’t produce enough vacuum for power brakes. What are my options?
A: This is due to the aggressive camshaft with a tight 108-degree lobe separation angle. Your solutions are:
-
Install a Vacuum Canister: Adds a reservoir to store vacuum for several brake applications.
-
Upgrade to an Electric Vacuum Pump: Provides a consistent and reliable vacuum source specifically for brakes.
-
Convert to Manual Brakes: Eliminates the need for vacuum entirely.
Q2: Why is a 2,500+ RPM stall converter recommended?
A: The aggressive camshaft makes very little power at low RPMs. A high-stall torque converter allows the engine to rev into its power band (where it makes real horsepower) before fully engaging the transmission. Without it, the car will feel very sluggish from a stop.
Q3: Can I use this engine in my factory-equipped car?
A: While it will physically fit in any classic Chevy engine bay, its functionality is not “factory.” You must address the power brake vacuum issue and, for automatic transmissions, install the recommended high-stall converter. It also requires 91+ octane fuel.
Q4: What is the difference between a “long block” and a “mid-dress” engine?
A: A long block typically includes only the engine block, heads, and internal components. A mid-dress or semi-dress engine includes many of the external components needed to run, such as the intake manifold, distributor, water pump, and valve covers, saving you significant cost and hassle.
Q5: Is this a new or remanufactured engine?
A: The ATK HP101M is classified as remanufactured. It is built using a seasoned (used) OEM GM block that has been machined to exacting specifications and assembled with all-new performance internal and external components.
Pros and Cons
| Pros | Cons |
|---|---|
| Turn-Key Power: Massive 470 HP/490 TQ output with a proven component combination. | Low Vacuum Production: Cannot operate power brakes without an auxiliary vacuum pump or canister. |
| Mid-Dress Convenience: Includes intake, distributor, water pump, and covers for easier installation. | High-Stall TC Required: Needs a 2,500+ RPM stall converter for automatic transmissions to perform correctly. |
| Premium Components: Features Dart aluminum heads, forged internals, and an MSD distributor. | Premium Fuel Required: Must run on 91 octane or higher to prevent detonation. |
| Strong Value: Cost-effective way to get a high-horsepower, complete package. | Aggressive Manners: The lumpy idle and power curve are not suited for docile street cruising. |
| Hydraulic Roller Reliability: Offers the performance of a solid cam with easier maintenance and longevity. | Remanufactured Core: Built on a used GM block, not a brand-new casting. |
Conclusion & Ideal Use Case
The ATK HP101M 383 Stroker is a specialized tool for a specific job: delivering maximum, brutal horsepower in a street-legal package. It is not a gentle cruiser; it is a weapon for the drag strip that can be driven on the street.
This engine is perfectly suited for:
-
1967-1981 Camaros, Novas, and Chevelles
-
1955-1957 Chevy Hot Rods
-
Street/Strip Pro-Touring builds
-
Lightweight Track Cars
-
Any project where uncompromised power is the primary goal.
If you are building a weekend warrior or a strip-focused machine and are prepared to address its operational requirements (brakes, converter, fuel), the ATK HP101M offers an incredible power-to-dollar ratio and the visceral thrill only a big-cam stroker motor can provide.
