This Is A Metric And American Socket Head stainless steel Allen Bolt Kit And Fits The Top Half Of The LT-1/ LT-4 Engines. This 56 piece kit fits the top of the engine from the intake manifold up. The kit also includes Mil Spec Stainless AN flat washers which will fit in the tightest spots. The kit consists of Allen bolts for the following: Fuel Rails, Top plate, Throttle body, Throttle bracket, Valve Covers, and the Thermostat Housing. The kit also includes a stud kit for the EGR.