Fits small block or big block Chevy V8's, Housing is CNC-machined from a billet of 6061-T6 aluminum, .500” steel shaft is supported by a sealed ball bearing and a long sintered bushing, Several springs and stop bushings are supplied so you can tune an advance curve to match your application, A precision machined reflector is attached to the shaft which triggers the magnetic pick-up mounted in the housing MSD 85551 Chevy Billet Distributor Sku # 54785551 Mfr. Part # 85551 Condition New Brand MSD Sold Each Details
You can't go wrong with the best selling MSD Billet Distributor! The housing is machined from a billet of 6061-T6 aluminum on a state-of-the-art CNC machine producing exact tolerances. For high rpm stability, a .500” steel shaft is supported by a sealed ball bearing and a long sintered bushing. This shaft also receives a QPQ coating for friction reduction and resistance to corrosion. A precision machined reluctor is attached to the shaft which triggers the magnetic pick-up mounted in the housing. This high output magnetic pick-up is the most accurate way to trigger your ignition. Plus, with no moving parts to wear or adjust, the pick-up is maintenance free! Just above the pick-up is MSD’s adjustable mechanical advance assembly. Different springs and stop bushings are supplied so you can tune an advance curve to match your application.
Fits Small Block or Big Block Chevy V8.
- CNC machined billet aluminum housing and billet aluminum base
- Easy-to-adjust mechanical advance with supplied springs and stop bushings
- Maintenance-free magnetic pickup and precision reluctor create stable trigger signals throughout the RPM range
- Polished steel shaft is QPQ coated and guided by a sealed ball bearing and extra long sintered bushing
- Advance plate and weights are fine blanked from Chromoly steel and QPQ coated for friction reduction
- Mechanical advance assembly can be locked out for crank trigger systems
- Advance weight pins are staked and tig welded to the plate
- Nylon pads ensure smooth operation of the advance weights
- Special oil tract improves lubrication to the distributor and cam gear
- O-ring seals can be added to modified blocks to improve oil pressure control
- Supplied with an HEI style distributor cap and rotor (accepts MSD Cap-A-Dapts)
Specs External Ignition Box Required Yes Cap Type HEI / Male Cap Terminal Style HEI / Male Advance Type Mechanical Trigger Style Magnetic Hall Effect No Sync Signal No Trigger Sensors Single Gear Material Iron Gear Rotation Standard Distributor Cap Color Red Ignition Box Required Yes Mechanical Tach Drive No Slip Collar No Housing Material Billet Aluminum Housing Finish Natural Rotor Rotation Clockwise Emissions California EO Approved Marine Use No MFG. Part # 85551 Sold in Quantity Each GTIN Code 085132855513 Reviews Yes. Rated by Jay on April 03, 2026
Summary: Street stock dirt car. Msd products are always reliable.
Yes, I recommend this product.
Msd power Rated by Hi Desert Chevy on January 10, 2026
Summary: Works great
Yes, I recommend this product.
I would buy this product again Rated by Strokerace on May 18, 2025
Summary: Put it in engine fired right up
Yes, I recommend this product.
Works great Rated by Gibby on January 13, 2025
Summary: As usual no problems with MSD. Gives a little extra firewall clearance.
Yes, I recommend this product.
I will buy again Rated by Flathead on February 03, 2024
Summary: Easy inst
Yes, I recommend this product.
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