Chevy 350 Crate Engine

Specification

The 350 crate engine is a widely used Gen I Chevy small-block V8 with a 5.7-liter (350 cubic inch) displacement, commonly built around a cast-iron block with 4-bolt main caps for added bottom-end strength and durability. It features a 4.00-inch bore and 3.48-inch stroke, a configuration known for delivering strong low-end torque and reliable mid-range performance. Internally, most versions use a forged steel or cast crankshaft, steel connecting rods, and cast or hypereutectic aluminum pistons, while airflow is handled by cast-iron or aluminum cylinder heads with typical valve sizes of 1.94-inch intake and 1.50-inch exhaust, though larger valves are used on higher-performance builds.

Compression ratios vary depending on the intended application, usually ranging from 8.5:1 to 9.6:1 for street and performance engines, allowing compatibility with pump gasoline. Output levels span a wide range, from around 210 horsepower and 300 lb-ft of torque in base configurations to over 400 horsepower and 410 lb-ft of torque in high-performance or turn-key versions, making the 350 crate engine a versatile choice for muscle cars, classic restorations, street rods, and light-duty trucks. For those seeking modern LS-based alternatives with similar displacement, the 5.3 LS engine and 6.0 LS engine offer comparable power with improved fuel efficiency and modern engine management.

Variants

SP350/357

The SP350/357 crate engine is a strong base performance option that blends classic Gen I small-block architecture with modern refinements for improved reliability and power delivery. Producing approximately 357 horsepower, it is designed for enthusiasts who want a noticeable performance upgrade without sacrificing street manners. This variant typically features improved cylinder heads, a mild performance camshaft, and a balanced rotating assembly, delivering smooth idle characteristics, strong low-end torque, and dependable mid-range power. It is well-suited for classic muscle cars, cruisers, and restomod builds where drivability and longevity are priorities.

SP350/385

The SP350/385 crate engine is a more aggressive performance-oriented upgrade, delivering around 385 horsepower with a higher-revving personality. It incorporates enhanced airflow components such as higher-flow cylinder heads, a more aggressive camshaft profile, and upgraded valvetrain components to support increased RPM capability. This engine offers stronger top-end power while still maintaining reasonable street usability, making it a popular choice for performance street cars and weekend racers. The SP350/385 strikes an effective balance between classic small-block torque and modern performance expectations.

SP350 Turnkey

The SP350 Turnkey variant is designed for maximum convenience, offering a fully assembled and dressed engine ready for installation. These engines come equipped with essential accessories such as a carburetor or fuel system components, distributor, alternator, water pump, and pulleys, significantly reducing installation time and complexity. Built on the same performance foundations as the SP350/357 or SP350/385, the turnkey package is ideal for builders who want reliable performance without sourcing individual components. For those considering different small-block options, the Ford 302 crate engine provides a comparable alternative with Ford-specific fitment for Mustang and F-Series applications.

The final evolution of the 350 came with the Vortec 5.7L, offering advanced cylinder heads and improved airflow. Producing up to 255 horsepower and 330 lb-ft of torque, the Vortec engine was featured in Silverado, Tahoe, and Suburban models. With its balance of efficiency and performance, it remains a top crate engine choice for modernized swaps and rebuilds.

Frequently Asked Questions