KING or ACL Bi-Metal Bearings Standard Crank/Connecting Rods.
Types of King Bi-metal Bearings.
SI - is silicon containing material for the medium load gasoline engines,
particularly engines using nodular cast iron crankshafts
Ford:
351C (1970-74).
351CJ (1970-74).
351M (1975-82).
400 (1971-82).
More information you can get here.