As of November 2015, Chevrolet manufactures five models of its 350 engine, with the lowest-end 290 HP Deluxe model creating 290 horsepower at 5,250 revolutions per minute and 326 foot-pounds of torque between roughly 3,250 and 4,625 RPM. It is a V8 engine displacing 350 cubic inches with an eight-to-one compression ratio. The engine has a cast-iron block, powdered steel connecting rods, cast-aluminum pistons and intake manifold, and a nodular iron crankshaft. Chevrolet recommends 87 octane fuel.
The SP350 Turn-Key is Chevrolet's highest-end 350 engine. It generates 385 horsepower at 5,600 RPM and 435 foot-pounds of torque between about 3,000 and 5,000 RPM. Chevrolet designed this engine for higher-RPM operation than its other 350 models by including fast-burn, aluminum cylinder heads; beehive-style valve springs; larger valves and a forged steel crankshaft. This engine has a 9.6-to-one compression ratio, and Chevrolet therefore recommends that it use at least 91 octane fuel. All 350 engine models use carburettors rather than fuel injectors.
Chevrolet sells its five models of 350 engines as crate motors -- stand-alone engines purchased in crates, rather than as components in cars. Turn-key crate motors are engines that come with the all the pieces necessary to integrate them into cars, including starters, fuel pumps, air conditioner pumps, alternators and distributors.