Seals It 2" To 2 1 2" Stacks Sprint Car Air Box Seal Aluminum Rubber 3350624 12 120 Highly Recommended For Any Application 38783 Highly Recommended For Any Application Making Over 400 HP Features:Designed for street performance use with a mechanical and vacuum advanceMust be used with an MSD Ignition ControlSupplied with an HEI style distributor cap and rotor (accepts Cap A Dapts)O ring seals can be added to modified blocks to improve oil pressure controlSpecial oil tract improves lubrication to the distributor and cam gearNylon pads ensure smooth operation of the advance weights┬ ¼Î“ÇáAdvance weight pins are staked and tig welded to the plateMechanical advance assembly can be locked out for crank trigger systemsAdvance plate and weights are fine blanked from chrome moly steel and QPQ coated for friction reductionPolished steel shaft is QPQ coated and guided by a sealed ball bearing┬ ¼Î“ÇáMaintenance free magnetic pickup and precision reluctor create stable trigger signals throughout the rpm rangeCNC machined billet aluminum housing and billet aluminum baseVacuum advance canister for improved economy (can be locked out)┬ ¼Î“ÇáEasy to adjust mechanical advance with supplied springs and stop bushingsCARB E motorsports From asphalt and dirt track racers Seals It rod end seals get the job done