Keith Black KB128-030 Hypereutectic Flat Top Piston Set for Chevy 400

KB Performance hypereutectic pistons are made from 390 aluminum alloy and heat-treated to T6 standards, delivering exceptional strength and durability for high-performance small block Chevy 400 builds. Designed for 4.125" bore x 3.75" stroke engines, this KB128-030 set features a 6.0" rod length configuration with 4.155 in. bore (.030" oversize).

Key Features:

• 100% CNC machined and T-6 heat treated from 16%-18% silicon Hypereutectic alloy
• T-5 heat treated pistons offer reduced thermal expansion, allowing tighter clearances
• Fully machined crowns and valve reliefs with flat top design
• Drilled oil returns and pin oil supply, .072'' spiral wound retaining ring
• High upper compression-ring location, gas-accumulator groove
• Full floating wrist pins with 360° pressure pin oiling
• Lightweight, rigid-rib skirt design that stabilizes the piston in the bore
• Piston/Pin Weight: 475 g

Compression Ratios: 58cc=12.3, 64cc=11.64, 76cc=10.0

These pistons fit tighter than forged types, provide improved oil control, reduce blow-by, increase ring life, and eliminate cold start-up knocking.