Depending on where, and how bad the crack is, some heads can be repaired. When I was running the connecting rod department at a big machine shop in Nashville Tennessee, we did quite a bit of business with a repair facility called Diesel Cast Welding. Of course, it was probably cost-effective to repair heads on big Diesel rigs. Whether or not the repair cost would be worthwhile on a stovebolt head, I'm not sure.
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!