The crank in the picture is a forged item, not cast. Be sure to replace it with the same style if you're going to rebuild it to the higher HP standard. That one can probably have that one journal welded and reground if you have problems finding another forged shaft. Some of the later model low HP 327's had cast cranks. The way to recognize the HD shaft is to look for the wide parting line on the crank throw, like your current shaft. Cast cranks have a very narrow parting line.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!