If you have a slightly taller block or have decked the heads, the distance between the distributor mounting pad and the cam gear/oil pump drive may be different. MSD offers these Distributor with an adjustable slip collar with 1. 5" of adjustment so you can be sure the distributor is installed correctly. The distributor shares the same features of the standard Pro-Billet Chevrolet model including a ball bearing guide, long sintered lower bushing and an oil seal. To trigger the MSD Ignition a maintenance-free magnetic pick-up is secured in the billet base of the distributor. Just above this pick-up assembly is an adjustable mechanical advance assembly. Features: CNC machined billet aluminum housing and billet aluminum baseEasy-to-adjust mechanical advance with supplied springs and stop bushingsMaintenance-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 bearing and extra long sintered bushingAdvance 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 weightsSpecial oil tract improves lubrication to the distributor and cam gearO-ring seals can be added to modified blocks to improve oil pressure controlSupplied with an HEI style distributor cap and rotor (accepts Cap-A-Dapts)Must be used with an MSD Ignition ControlWill not accept a vacuum advance canisterNo CARB Exemption Order NumberAdjustable slip collar for engines with modified deck heightsPit Stop USA offers MSD Pro-Billet Chevrolet V8 Distributor w/ Slip Collar 85561 at low everyday prices. Be sure to check out all of our products from MSD including MSD GM Distributors.