MSD PRO BILLET DISTRIBUTOR FITS HOLDEN V8 253-304-308 MECH ADVANCECNC machined billet aluminium housing and billet aluminium. 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 two sealed ball bearings. Advance plate and weights are fine blanked from chrome moly steel and QPQ coated for friction reduction. Mechanical advance assembly