ATK GM 350 408 HP HP34 Stage 1 Aluminum Head Long Block

ATK GM 350 408 HP HP34 High-Output Crate Motor Breakdown

ATK GM 350 408 HP HP34 stage 1 engines feature a high-output crate motor configuration designed for aggressive street-strip performance and durability. Built on a seasoned cast-iron block with lightweight aluminum cylinder heads, this 350ci reman engine optimizes power-to-weight ratios for muscle car and truck restorations. The assembly maintains superior valvetrain stability via an OE hydraulic roller camshaft, ensuring consistent torque delivery across the power band. This Stage 1 long block serves as a high-performance foundation for enthusiasts demanding maximum output from a traditional SBC platform.

Integrating this high-performance performance powertrain into your chassis requires specific induction and ignition components, as it arrives in an un-dressed state. While the ATK HP34 includes a factory-installed oil pan, valve covers, and timing cover, builders must provide their own intake manifold and water pump. The modern one-piece rear main seal effectively prevents fluid weeping, making this rebuilt long block a reliable choice for long-term drivability. This Stage 1 setup ensures maximum flexibility for custom tuning while providing a robust, precision-balanced rotating assembly.

Key Features of ATK High Performance HP34

• 5.7L 350ci displacement with high-flow aluminum cylinder heads.
• Verified 408 horsepower output for aggressive street-strip use.
• Hydraulic roller camshaft ensures stable and consistent performance.
• Internal and external balance configuration for smooth operation.
• One-piece rear main seal prevents common fluid weeping.
• Includes pre-installed oil pan, valve covers, and timing cover.
• Stage 1 un-dressed build allows custom induction system choice.

HP34 Include:

• Oil Pan
• Valve Covers
• Timing Cover