Threaded, adjustable billet collar easily adjusts to different intake manifold heights to optimize gear meshing Collar has an integrated hold-down Adjustment of rotor tip phasing can be accomplished without touching the distributor hold-down, the cap itself can be adjusted Rotor tip does not have to be rephrased after removing and reinstalling the distributor The sealing flange features an o-ring and gasket used to seal crankcase vacuum regardless of the collar height Housing features thick o-rings that can withstand frequent installation and removal The plastic on the distributor, cap, adapter and rotor is the same plastic Moroso uses on its distributors supplied to top NASCAR teams