The Street Pro-Billet Distributors are the perfect choice for powerful engines that see plenty of street time. The Street models share the same features as the small diameter models shown above, plus feature a vacuum advance. This canister provides improved economy and an accurate mechanical advance lets you dial-in an advance curve to match your driving needs. a magnetic pick-up produces accurate trigger signals that remain stable throughout the entire rpm range of your engine and is completely maintenance-free. Features: Billet housing is 5/8" smaller in diameter than stock Ford distributorsEasy-to-adjust mechanical advance with supplied springs and stop bushingsVacuum advance canister for improved economy (can be locked out)CNC machined billet aluminum housing and billet aluminum baseMaintenance-free magnetic pickup and precision reluctor create stable trigger signals throughout the rpm rangePolished steel shaft is QPQ coated and guided by a sealed ball bearingAdvance plate and weights are fine blanked from chrome moly steel and QPQ coated for friction reductionMechanical advance assembly can be locked out for crank trigger systemsAdvance weight pins are staked and tig welded to the plateNylon pads ensure smooth operation of the advance weightsSupplied with small diameter cap with HEI style terminals and race rotor (will accept 8441 Cap-A-Dapt)Must be used with an MSD Ignition ControlCARB E. O. ApprovedPit Stop USA offers MSD Ford Street Pro-Billet Distributor - Ford 351W V8 8478 at low everyday prices. Be sure to check out all of our products from MSD including MSD Ford Distributors.