Product Description
The ATK HP89 Chevrolet 350ci High-Performance Base Crate Engine is a professionally assembled small-block V8 designed for classic Chevrolet restorations, muscle-car projects, performance automotive builds, and compatible engine replacement applications.
Delivering 390 horsepower and 420 lb-ft of torque, this powerful 350 cubic-inch engine combines proven Chevrolet small-block architecture with performance-oriented components to provide a dependable foundation for naturally aspirated V8 applications.
Built around a 1996–2000 Chevrolet OE roller block, the HP89 features four-bolt main construction, a one-piece rear main seal, an OE reground crankshaft, powder-metal connecting rods, and hypereutectic pistons.
The engine’s 10.0:1 compression ratio works with its hydraulic roller camshaft, aluminum cylinder heads, and upgraded valvetrain components to support the advertised horsepower and torque figures.
A major performance feature is the ATK high-performance aluminum cylinder heads, which incorporate 64cc combustion chambers, 195cc intake runners, 2.020-inch intake valves, and 1.600-inch exhaust valves.
These cylinder heads work alongside a hydraulic roller camshaft featuring 220° intake and 224° exhaust duration at .050-inch lift, creating a performance-oriented engine configuration suited to compatible automotive projects.
Unlike the fully dressed HP89C engine, the ATK HP89 base-engine configuration provides the assembled long-block foundation without a complete external fuel, ignition, or intake system.
This allows automotive builders to select compatible intake manifolds, carburetors, ignition equipment, cooling components, and other accessories according to their specific vehicle requirements.
The base package includes essential engine-mounted components such as an oil pump, rear-sump oil pan, timing cover, and valve covers.
The ATK HP89 is particularly attractive for classic Chevrolet owners who want substantially more power than many original factory 350ci engines while retaining the familiar small-block Chevrolet architecture.
For restoration specialists and professional automotive workshops, the engine offers a convenient performance foundation that combines an assembled long block with the flexibility to select additional components.
Whether intended for a compatible Chevrolet Camaro, Chevelle, Nova, classic pickup, or professionally engineered custom vehicle, the ATK HP89 390HP Base Crate Engine delivers a powerful combination of traditional V8 performance, premium aluminum cylinder heads, and proven small-block construction.
Key Features
390 Horsepower Output
Produces an advertised 390HP, offering substantial naturally aspirated performance for compatible Chevrolet small-block applications.
420 lb-ft of Torque
Delivers 420 lb-ft of torque, supporting strong power delivery across the engine’s intended performance range.
Chevrolet 350ci Small Block V8
Features the traditional Chevrolet 350 cubic-inch V8 architecture used in numerous classic and performance automotive projects.
Four-Bolt Main Engine Block
Built around an OE roller block featuring four-bolt main construction and a one-piece rear main seal.
High-Performance Aluminum Cylinder Heads
Equipped with ATK aluminum heads featuring performance-oriented combustion chambers, intake runners, and valve sizes.
Hydraulic Roller Camshaft
Includes a hydraulic roller camshaft matched to the engine’s advertised 390HP performance configuration.
10.0:1 Compression Ratio
Features hypereutectic pistons and a 10.0:1 compression ratio.
Double-Roller Timing Chain
Equipped with a double-roller timing chain for its performance valvetrain assembly.
Performance Base-Engine Package
Provides an assembled engine foundation while allowing customers to select compatible external components.
Dynamometer-Proven Performance
The HP89 engine configuration is advertised as dynamometer-proven.
Two-Year Limited Warranty
Supported by the advertised ATK two-year, unlimited-mileage limited warranty, subject to applicable terms.
Technical Specifications
| Specification | Details |
|---|---|
| Manufacturer | ATK High Performance |
| Manufacturer Part Number | HP89 |
| Product Category | Performance Base Engine / Long Block |
| Engine Family | Chevrolet Small Block V8 |
| Store SKU | ATK-HP89-350V8-2141 |
| Displacement | 350ci / 5.7L |
| Cylinder Configuration | V8 |
| Advertised Horsepower | 390 HP |
| Advertised Torque | 420 lb-ft |
| Engine Block | 1996–2000 OE Roller Block |
| Main Configuration | 4-Bolt Main |
| Rear Main Seal | One-Piece |
| Bore | 4.040 Inches |
| Stroke | 3.480 Inches |
| Compression Ratio | 10.0:1 |
| Crankshaft | OE Reground |
| Crankshaft Balance | Internal Front / External Rear |
| Connecting Rods | OE Powder Metal, 5.7 Inches |
| Pistons | Hypereutectic |
| Piston Rings | Moly |
| Camshaft Type | Hydraulic Roller |
| Intake Duration @ .050 | 220° |
| Exhaust Duration @ .050 | 224° |
| Intake Valve Lift | .528 Inches |
| Exhaust Valve Lift | .536 Inches |
| Lobe Separation Angle | 110° |
| Timing Chain | Double Roller |
| Cylinder Heads | ATK High-Performance Aluminum |
| Combustion Chamber | 64cc |
| Intake Runner Volume | 195cc |
| Intake Valve Diameter | 2.020 Inches |
| Exhaust Valve Diameter | 1.600 Inches |
| Rocker Arm Ratio | 1.6:1 |
| Oil Pan | Rear Sump |
| Oil Pan Capacity | 5 Quarts |
| Oil Pump | Included |
| Recommended Fuel | 91+ Octane |
| Advertised Maximum RPM | 5,800 RPM |
| Dynamometer-Proven | Yes |
| Warranty | 2 Years / Unlimited Mileage, Limited Terms |
Engine Block / Internal Configuration
| Component | Details |
|---|---|
| Engine Architecture | Chevrolet Small Block V8 |
| Engine Block | OE Roller Block |
| Block Years | 1996–2000 |
| Main Bearing Configuration | 4-Bolt Main |
| Rear Main Seal | One-Piece |
| Displacement | 350ci |
| Bore × Stroke | 4.040″ × 3.480″ |
| Crankshaft | OE Reground |
| Front Balance | Internal |
| Rear Balance | External |
| Connecting Rods | OE Powder Metal |
| Rod Length | 5.7 Inches |
| Pistons | Hypereutectic |
| Compression Ratio | 10.0:1 |
| Piston Rings | Moly |
| Timing Chain | Double Roller |
The HP89 uses traditional Chevrolet small-block architecture combined with a performance-oriented rotating assembly and hydraulic roller valvetrain.
Cylinder Head / Valvetrain Configuration
| Component | Details |
|---|---|
| Cylinder Head Manufacturer | ATK High Performance |
| Head Material | Aluminum |
| Combustion Chamber | 64cc |
| Intake Runner Volume | 195cc |
| Intake Valve Diameter | 2.020 Inches |
| Exhaust Valve Diameter | 1.600 Inches |
| Camshaft Type | Hydraulic Roller |
| Intake Cam Duration | 220° @ .050 |
| Exhaust Cam Duration | 224° @ .050 |
| Intake Valve Lift | .528 Inches |
| Exhaust Valve Lift | .536 Inches |
| Lobe Separation Angle | 110° |
| Rocker Arm Ratio | 1.6:1 |
The combination of aluminum cylinder heads and hydraulic roller camshaft supports the engine’s high-performance airflow and power characteristics.
Fuel / Intake Configuration
| Component | Details |
|---|---|
| Engine Fuel Type | Gasoline |
| Recommended Fuel | 91+ Octane |
| Intake Manifold | Not Included |
| Carburetor | Not Included |
| Fuel Pump | Not Included |
| Fuel System | Selected Separately |
| Recommended Intake Type | Compatible Chevrolet Small Block Performance Intake |
| Engine Configuration | Base Engine |
The ATK HP89 allows customers to choose their own intake manifold and fuel-delivery equipment rather than purchasing a complete dressed-engine configuration.
Ignition / Electrical Configuration
| Component | Details |
|---|---|
| Distributor | Not Included |
| Ignition System | Application-Specific |
| Spark Plugs | Selected Separately |
| Spark Plug Wires | Not Included |
| Engine Computer | Not Included |
| Wiring Harness | Not Included |
| Recommended Ignition | Compatible Chevrolet Small Block System |
Cooling / Lubrication Configuration
| Component | Details |
|---|---|
| Oil Pump | Included |
| Oil Pan | Rear Sump |
| Oil Pan Capacity | 5 Quarts |
| Timing Cover | Included |
| Valve Covers | Included |
| Water Pump | Not Included |
| Cooling System | Vehicle-Specific |
| Oil Filter | Appropriate Compatible Filter |
| Lubrication Maintenance | Follow ATK Manufacturer Documentation |
Base Engine / Package Configuration
| Component | Details |
|---|---|
| Engine Package | Stage 1 Base Engine |
| Assembled Long Block | Included |
| Aluminum Cylinder Heads | Installed |
| Hydraulic Roller Camshaft | Installed |
| Oil Pump | Included |
| Oil Pan | Included |
| Timing Cover | Included |
| Valve Covers | Included |
| Intake Manifold | Not Included |
| Carburetor | Not Included |
| Distributor | Not Included |
| Water Pump | Not Included |
| Torque Converter | Not Included |
| Transmission | Not Included |
Important: HP89 is the base-engine model. It should not be advertised as the fully dressed HP89C, HP89CBLK, or HP89CPOL engine.
Engine Balance / Drivetrain Configuration
| Component | Details |
|---|---|
| Front Crankshaft Balance | Internal |
| Rear Crankshaft Balance | External |
| Recommended Harmonic Balancer | PowerBond PB1046-N |
| Recommended Flexplate | Pioneer FRA-159 |
| Rear Main Seal | One-Piece |
| Transmission Compatibility | Application-Specific |
| Engine Mounting | Chevrolet Small Block Configuration |
| Drivetrain Requirements | Vehicle-Specific |
What’s Included
| Included Component | Details |
|---|---|
| ATK HP89 Chevrolet 350ci Base Engine | 1 Unit |
| Four-Bolt Main Engine Block | Included |
| Crankshaft | Installed |
| Connecting Rods | Installed |
| Hypereutectic Pistons | Installed |
| Moly Piston Rings | Installed |
| Hydraulic Roller Camshaft | Installed |
| Double-Roller Timing Chain | Installed |
| Aluminum Cylinder Heads | Installed |
| Rocker Arms & Valvetrain | Installed |
| Engine Oil Pump | Included |
| Rear-Sump Oil Pan | Included |
| Timing Cover | Included |
| Valve Covers | Included |
| Intake Manifold | Not Included |
| Carburetor | Not Included |
| Fuel Pump | Not Included |
| Distributor | Not Included |
| Water Pump | Not Included |
| Harmonic Balancer | Not Included |
| Flexplate / Flywheel | Not Included |
| Spark Plug Wires | Not Included |
| Transmission | Not Included |
Vehicle / Installation Compatibility
The ATK HP89 Chevrolet 350ci V8 Base Engine is intended for compatible Chevrolet small-block automotive applications.
| Vehicle Application | Compatibility Considerations |
|---|---|
| Chevrolet Camaro | Engine Mounting, Cooling and Drivetrain |
| Chevrolet Chevelle | Oil Pan and Chassis Clearance |
| Chevrolet Nova | Engine Bay and Mounting Requirements |
| Chevrolet Impala | Engine and Transmission Compatibility |
| Chevrolet El Camino | Application-Specific Fitment |
| Classic Chevrolet Trucks | Engine Mounting and External Accessories |
| GMC Trucks | Chevrolet Small Block Compatibility |
| Custom Automotive Projects | Complete Drivetrain and Chassis Verification |
The listed rear-sump oil pan may not fit certain Chevrolet configurations, including some Chevelles, Corvettes, and 1962–1967 Chevy II vehicles.
Vehicle compatibility must be confirmed before purchase.
Ideal Applications
Classic Chevrolet Restoration: Suitable for compatible Chevrolet restoration projects requiring a high-performance 350ci V8.
Muscle-Car Projects: Provides a performance engine foundation for appropriate classic muscle-car applications.
Custom Automotive Builds: Allows professional builders to select external components that match their intended vehicle configuration.
Classic Truck Projects: Useful for compatible Chevrolet and GMC truck restorations with suitable drivetrain equipment.
Professional Engine Replacement: Suitable for automotive workshops handling performance long-block installation and restoration projects.
Product Advantages
The ATK HP89 Chevrolet 350 Base Crate Engine combines the proven small-block Chevrolet V8 platform with performance-oriented internal components.
Its 390HP rating, 420 lb-ft torque, aluminum cylinder heads, 10.0:1 compression ratio, and hydraulic roller camshaft provide a strong foundation for compatible classic Chevrolet projects.
The base-engine format offers flexibility to customers who prefer selecting their own intake, ignition, fuel-delivery, and cooling components.
For automotive restoration businesses and performance builders, the HP89 offers a convenient assembled engine foundation without requiring the purchase of a fully dressed engine package.
Safety & Installation Notice
Professional automotive installation is recommended. Verify engine mounting, oil pan clearance, transmission compatibility, cooling, fuel-system requirements, and applicable emissions regulations.
The HP89 is advertised as a non-emissions performance engine and should not be assumed legal for pollution-controlled street vehicles.
Warranty Information
2-Year / Unlimited-Mileage Limited Warranty
Warranty coverage is subject to ATK’s applicable terms, including installation requirements, exclusions, core-return conditions, and claim procedures.
Product Highlights
ATK HP89 Chevrolet 350 Base Crate Engine 390 Horsepower 420 lb-ft Torque 350ci / 5.7L Small Block V8 Four-Bolt Main OE Roller Block One-Piece Rear Main Seal High-Performance Aluminum Cylinder Heads Hydraulic Roller Camshaft 10.0:1 Compression Ratio Hypereutectic Pistons Double-Roller Timing Chain 64cc Combustion Chambers 195cc Intake Runners Performance Base Engine Configuration Dynamometer-Proven Performance 2-Year / Unlimited-Mileage Limited Warranty
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