From my experience with other engines, cast cranks have a relatively wide parting line, and forged cranks have a narrow, more well-defined parting line. I'm not sure this is applicable to these crankshafts or not, though.
JD
See if this applies...
[*]The second visual difference is the bolt circle itself. The forged crankshaft has an evenly spaced bolt circle. Since there are no added weights to either the torque converter or the flex plate on an engine with a forged crankshaft, the flex plate can be bolted to the crankshaft in any position. On the cast crankshaft, one bolt hole on the bolt circle is off-set so that the flex plate can be bolted on in only one position.
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Mike8675309>There are often obvious grind marks on a forged parting line as the excess metal is ground off.
Any idea if SC cranks were twist or non-twist die pressed?