these valves fit small and big block chevy engines with screw-in style oil lifter ... retarding the cam application part no chevy sb 283-400 long style stock replacement ... crankshaft key 983g chevy sb 283-400 short style stock ... replacement crankshaft key 984g chevy sb 283-400 bb 396-454 short style ... silver 2° offset crankshaft key 987g chevy sb 283-400 bb 396-454 short style ... stock rockers only 8/set part no 1015 chevy ford pontiac advance retard cam ... dowel pin hole must be drilled for chevy 283-454 and all chrysler b block ... for stock rocker arms description chevy 283-400 pontiac v8 and ford 289-302- ... 3513/8 stud chevy 396-454 pontiac heavy duty 7/16 stud ... and causing erratic timing description chevy 265-400 std sprocket w/flat face timing ... cover chevy 396-427-454 std sprocket part no 920g ...