Holley 125-500 Power Valve Check Ball Protection Kit

The Holley 125-500 Power Valve Check Ball Kit provides essential protection for your carburetor's power valve against backfire damage. This complete kit prevents fuel from flowing backward through the main metering block, safeguarding the power valve diaphragm from rupture caused by intake manifold backpressure.

Complete Kit Includes:

• Check ball to prevent reverse fuel flow
• Spring for proper check ball tension
• Brass seat for durable sealing
• Properly sized drill bit with integrated depth stop
• Detailed installation instructions

Installation requires drilling a precise hole in the main metering block to accommodate the check ball assembly. The included drill bit features a built-in stop collar to ensure accurate drilling depth, preventing damage to the metering block. This simple upgrade is compatible with most Holley 4150 and 4160 series carburetors and can significantly extend power valve life, especially in high-performance applications prone to backfiring during deceleration or aggressive tuning.