12691674 - Chevrolet Performance SP & ZZ Small-Block Partial (short block) Engine

With it's 4-Bolt main block and forged steel crankshaft, The SP/ZZ Partial Engine is a proven winner. Used as the foundation for thousands of SP and ZZ crate engines including the legendary ZZ6, The SP/ZZ partial engine has a long history of performance and durability. Its forged LT4 powdered metal connecting rods and light flat top hypereutectic pistons ensure high RPM performance. Provisions for a steel roller camshaft and one piece rear main seal are "state of the art". Technical Note: Does not include camshaft, timing chain, sprockets, front cover, oil pump, oil pan, balancer, or flexplate.

Compression Ratio is dependent upon the combustion chamber size of the cylinder head that you use
58cc-10.0:1
62cc-9.8:1
64cc-9.6:1

• Block - Part# 10105123 Cast iron, 4 Bolt main, With 1 piece Rear main Seal
• Crankshaft - Part# 12556307 Forged 1053 Steel, Internally Balanced.
• Connecting Rods - Part# 10108688 5.7" Powdered metal.
• Pistons - Part# 10159436 Hypereutectic, flat top , With offset pins. Same piston that is used in Corvette LT1 engines.
• Also Includes: Rings Bearings, and Stainless Steel Freeze Plugs
• Does Not Include: Any valvetrain components, timing chain, oil pump, oil pan, timing cover, balancer or flywheel.