Manley 290300HX SBC Rotating Assembly Stroke Bore Stroker Kit - 434 4.000 4.125

The Manley 290300HX is a complete Small Block Chevy 434 cubic inch rotating assembly designed for high-performance and racing engine builds. This stroker kit pairs a 4.000" stroke crankshaft with 4.125" bore pistons, delivering the displacement and power potential that serious SBC builders demand.

At the heart of this kit is a Manley 4340 forged steel lightweight crankshaft that has been heat treated, stress relieved, shot peened, nitrided, and 100% Magna Fluxed for maximum strength and durability. The crank features a non-twist design to maintain precise rod journal alignment under extreme load.

Key Features:

• 4340 forged steel H-beam connecting rods — heat treated, stress relieved, shot peened, nitrided, and 100% Magna Fluxed
• ARP cap screws — rated for high-horsepower applications
• 2618 forged aluminum Platinum Series pistons — engineered for strength and thermal stability
• Premium Chrome Moly wrist pins included
• 4.000" stroke crankshaft with 350 main journal sizing
• 4.125" bore piston diameter
• Precision internally balanced by Manley in-house
• Designed for Small Block Chevy (SBC) applications

Manley's SBC 434 rotating assemblies are engineered to support demanding power levels while maintaining the reliability expected from a Manley-built rotating assembly. This kit provides the foundation for a high-displacement SBC stroker build used in street performance, drag racing, and circle track applications.