Mallory Ignition 29371 Circuit Guard for UniLite MBI E-Spark Electronic Ignition Modules

The Mallory 29371 Circuit Guard is a compact electronic ignition protection device engineered to safeguard Mallory UniLite, MBI, and E-Spark ignition modules from damaging voltage spikes, power surges, and electrical noise. It combines active power filtering against positive voltage transients with negative spike protection, delivering dual-layer defense in a single plug-in unit.

Voltage spikes are a common threat in vehicles with "noisy" electrical systems — often caused by worn or dirty alternator brushes, corroded battery terminals, or oxidized electrical connections. Left unprotected, these transients can destroy expensive ignition modules. The 29371 clamps and regulates these spikes before they can reach the module.

Key Features:

• Dual-mode protection: active power filtering for positive spikes and surges plus negative spike suppression
• Simple plug-in installation — connects inline between the distributor connector and the wiring harness
• Compact design mounts directly onto most distributor housings via included Velcro
• Wiring harness and wire connectors included
• Compatible with all Mallory UniLite, MBI, and E-Spark electronic ignition modules
• Fits UniLite distributor series Nos. 37, 38, 45, 46, 47, 83, 86, 91, and 93; all MBI distributor series 42, 50, 57, and 87; all MBI breakerless electronic conversion kits; and HyFire systems
• Legal for use on emissions-controlled, non-emissions-controlled, and race-only vehicles
• Sold individually

The Mallory 29371 Circuit Guard is an essential protection upgrade for any vehicle running a Mallory electronic ignition distributor, providing peace of mind and long-term reliability for your ignition system investment.