Fits: SBC Cylinder Heads including 18 degree and 23 degree, clears Jesel, T&D style Rocker Shaft Assemblies 3-1/2" Tall Fabricated from superior quality aluminum, ultra lightweight One-piece billet rail is machined to ensure a precision flat surface for superior sealing Tall enough to clear all popular rocker combinations Air-tight sealing allows the engine to pull greater vacuum for improved ring seal and power Notched at each mounting location with socket-sized clearances for quick installation and removal Mounting fasteners included *Not legal for sale or use on pollution-controlled vehicles