Chevrolet Performance Parts SP350/357 Base Engine

The SP350/357 is Chevrolet Performance's economical take on the small-block, rated at 357 horsepower and built around a strong rotating assembly inside a new CNC-machined four-bolt-main block. The maker calls this a 24-horsepower gain over its own 350 HO crate engine, helped along by a roller camshaft tuned for drivability and airflow.

What keeps the cost down

Instead of aluminum, this engine uses economical cast-iron Vortec cylinder heads, matched to cast-aluminum pistons and a forged-steel crankshaft, with a one-piece rear main seal. The rear of the engine is externally balanced for the flywheel or flexplate, while the front sits internally or neutrally balanced at the harmonic balancer; bore and stroke come in at 4.000 by 3.480 inches.

What ships and what does not

Valve covers and a harmonic balancer ship with this Base package, while fuel, ignition, and accessory-drive parts are entirely up to the installer: no carburetor, manifold, distributor, pump, or wiring of any kind rides along in the crate. Coverage on this crate engine runs 24 months or 50,000 miles (80,000 km), whichever comes first. If it is going into a vehicle registered in California, confirm current engine-swap compliance rules first.

Q: Does it come with a carburetor or intake manifold? No, this Base engine leaves both out, along with the distributor, so plan to add your own induction and ignition.