Chevy LS1 Underdrive Steel Elastic Harmonic Damper Balancer Only (1/2) They are ground and thread-rolled

They are ground and thread-rolled after heat treatment to ensure the exacting tolerances that Speedmaster requires for all of their fasteners

The main difference is that there is an open area under the plenum chamber

In today's higher rpm engines

Speedmaster cylinder head valvetrain kits offer a comprehensive solution for revitalizing your engine's cylinder heads

Chevy LS1 Underdrive Steel Elastic Harmonic Damper Balancer Only (1/2) They are ground and thread-rolledSpeedmaster K1045 steel enclosed elastic dampers are tested to 12,500 RPM for explosion proof racing application. The "S" shape gap between inner and outer ring is press inserted with sulfated elastic rubber to ensure the damper will not disintegrate under any circumstance. All dampers are tested to withstand 15 tons press force without separation or deterioration.