Unless the cracks are gapped open a bunch, just have it ground flat, deep enough to get rid of any glazed areas. Minor heat checks don't usually give a problem unless the flywheel is being abused by high RPM launches and kamikaze clutch dumps.
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!