Manley 39555H Engine Crankshaft Rotating Assembly BBC 555ci 4.250" Stroke / 4.560" Bore

The Manley 39555H is a complete rotating assembly engineered for Chevrolet Big Block engines displacing 555 cubic inches. Built as a precision-matched system, this assembly combines a forged crankshaft, high-strength connecting rods, and premium forged pistons — all selected and balanced to work together under extreme RPM and cylinder pressure. With a 4.250-inch stroke and 4.560-inch bore, and a +43cc dome piston volume, this kit is purpose-built for serious high-output engine builds targeting 900 to 1,500 horsepower depending on rod bolt specification. Clevite series main and rod bearings are specified, and the assembly is designed for standard deck blocks with center counterweights.

Key Features:

• 4340 forged steel crankshaft (Manley P/N 190290) — 4.250-inch stroke
• 4340 forged steel H-beam connecting rods (Manley P/N 14062) — 6.385-inch length — fitted with 7/16" ARP 8740 cap screws standard; ARP 2000 cap screws optional
• 2618 forged aluminum Platinum Series dome pistons (Manley P/N 697880) — 4.560-inch bore, +43cc volume
• Piston ring set included (Manley P/N 46558)
• Clevite series main and rod bearings specified
• Compression ratio: 14.90:1 with 112cc heads / 14.00:1 with 118cc heads / 13.20:1 with 124cc heads
• Horsepower capability: up to 900 HP with ARP 8740 rod bolts; up to 1,500 HP with optional ARP 2000 rod bolts
• Designed for standard deck Big Block Chevrolet blocks with center counterweights
• Displacement: 555 CID

Manley's rotating assemblies are built for engine builders who demand precision, consistency, and confidence at the limit of performance. Each component is manufactured to tight tolerances to reduce friction and maximize load-handling capability. This assembly is intended for Chevrolet Big Block applications and is a natural fit for race, marine, or high-performance street engine builds in that platform.