Manley 39555X Big Block Chevy Rotating Assembly Stroke Bore Dome - 555ci 4.250 4.560 43cc

The Manley 39555X is a complete Big Block Chevy (BBC) 555ci rotating assembly kit engineered for serious high-performance and racing applications. Built around a 4.250" stroke crankshaft and designed for a 4.560" bore, this kit delivers the displacement and durability needed to support demanding power builds. The "X" suffix designates Manley's optional "X" Series rod bearings, which feature an additional .001" extra clearance for improved oil flow in high-performance applications.

Key Specifications:

• Application: Big Block Chevrolet (BBC)
• Total Displacement: 555 cubic inches
• Crankshaft Stroke: 4.250"
• Bore Size: 4.560"
• Piston Dome Volume: 43cc
• Rod Bearing Series: "X" Series (.001" extra clearance)

Kit Includes:

• Manley forged 4340 steel crankshaft
• Manley connecting rods (H-Beam or I-Beam per configuration)
• Manley forged pistons with 43cc dome
• High-performance piston rings
• Clevite "H" Series rod bearings (X-Series, narrowed) and main engine bearings

Construction Highlights:

• Crankshaft is heat treated, stress relieved, shot peened, nitrided, and 100% magnafluxed
• Micro-polished large radius journals for reduced friction and wear
• ARP 8740 cap screws standard; ARP 2000 cap screws available as an upgrade for higher horsepower applications
• Designed for standard deck Big Block Chevy blocks (4.000"–4.375" stroke range)
• Factory balanced to within +/- 1% of bobweight

Manley Performance has been a trusted name in high-performance engine internals since 1966, supplying components for everything from street builds to full race engines. The Manley 39555X BBC 555ci rotating assembly is a proven foundation for builds targeting serious power output with the reliability and precision that Manley is known for.