MSD Distributor Pro-Mechanical Black Cap Black Housing Chevy Big/SB (MSD-85555) 85555

MSD Pro-Billet distributors share the same CNC machining techniques as the rest of the MSD distributor line. They feature a housing that's machined from high-quality 6061-T6 aluminum for durability and show-quality looks. Their oversized shaft receives a QPQ coating for friction reduction and corrosion resistance, with the added strength of two sealed ball bearings that guide the shaft accurately at well over 10,000 rpm. An extra-long sintered bushing replaces the ball bearing at the bottom of Chevrolet models. TIG-welded on top of the polished steel shaft is MSD's accurate mechanical advance assembly. The weights are supported by nylon pads that allow the advance to operate smoothly throughout the rpm range. For all-out racing, the advance mechanism can also be easily locked out. To accurately trigger the ignition, a high-output magnetic pickup is bolted to the base. This pickup produces a precise trigger signal that will never vary more than one degree at any rpm. A durable gear is installed for performance applications, and an MSD red cap with brass terminals and race rotor is supplied. They're available in standard and small diameter models for applications with limited clearance, and require the use of a separate ignition box such as an MSD 6, 7, 8, or 10 Series ignition.