The Cast Crankshaft has a narrow parting line like shown in Fig 50.1
The Forged Crankshaft has a wide parting line like shown in Fig 50.1a
NOTE: All crankshafts from 1955 up to about 1963 were Forged using SAE 1046 alloy steel. In 1967 there was a change in the material used in the forged crankshafts was changed from SAE 1046 to SAE 1053 alloy steel .