Along with the Blow-By Racing CNC’d heads and cams, Matt’s installing the company’s cam lockouts. These lockouts allow you to lockout the camshaft either fully advanced or fully retarded to keep the valves from coming into contact with the pistons. The higher-lift camshafts, if not locked out, would most likely cause piston-to-valve clearance issues. Factory ’05-’10 Mustang Three-Valve engines feature variable cam timing. These lockouts take the “variable” part out of the equation and lock the cam timing in one spot. Simply remove the sprocket’s front cover, insert cam lockout, and reinstall the sprocket cover.