MSD 85812 Cast Iron Distributor Gear Ford 351C 351M 400 429 460 FE

The MSD 85812 is a cast iron distributor gear engineered for Ford big block and Cleveland/Modified series engines. A distributor's ignition timing accuracy depends entirely on the quality of its drive gear, and MSD has invested extensively in metallurgical research, heat treatment testing, and surface coating evaluation to deliver a gear built for long service life and precise camshaft-to-distributor mesh.

Excessive gear clearance causes timing fluctuation across the rpm range, resulting in lost power. MSD addressed this by designing the 85812 as an oversized gear for a tighter, more accurate mesh between the camshaft and distributor drive gears. The result is stable, consistent ignition timing from idle to redline.

Key Features:

• Proprietary formulated ductile iron — purpose-engineered alloy for strength and durability under high-load conditions
• Melonite QPQ coating — low-friction surface treatment that reduces friction and minimizes initial break-in wear
• Micro-polished contact surface — smooth finish promotes even gear mesh and reduces scuffing
• Increased outer hardened layer thickness (RC 55–60) — deeper case hardening for extended wear life
• Interstitial carbide concentration — improves wear resistance and running properties throughout the gear's service life
• 0.531 in. shaft diameter — correct fitment for Ford 351C, 351M, 400, 429, 460, and 332–428 FE engines
• Roll pin included — no additional drilling required for installation
• Sold individually

The MSD 85812 is a direct-fit replacement distributor drive gear for Ford big block, Cleveland, Modified, and FE-series V8 applications using iron camshafts. It is compatible with MSD distributor assemblies designed for these engine families.