I didn't really mean to put emphasis on the cracked aspect just that they are the only heads I have ATM. Seats and some Fluidweld will take care of the cracks in most cases. J.Rob
The vast majority of cracked Magnum heads I've seen had visible cracks but no ill effects on a running engine. They're not all fatal. I have a set on my shelf that ran fine with no issues but "were junk"...lol.