Chrysler 426,440 Pro-Billet Distributor Small Diameter Housing Allows The Distributor To Fit Tight Block And Head Combinations MSD IgnitionSince many Chrysler enthusiasts use the B1 head or aftermarket valve covers, these Pro Billet Chrysler Distributors have been designed with a small diameter housing. Smaller diameter CNC machined billet aluminum housing and billet aluminum base clears aftermarket heads and valve covers No CARB Exemption Order Number Advance weight pins are staked and tig welded to the plate Mechanical advance assembly can be locked out for crank trigger systems