In a sense, yes. However, most out there are cracked and the engines are running fine. I'm not saying cracks in the head are fine, but it doesn't seem to effect anything.
For me, it’s a tough sell to have someone spend money on heads that are visibly cracked.
If you’re lucky enough to have a pair of them that don’t have the exhaust seats sunk down into no man’s land, and can get away with a very minimal amount of machine shop servicing........that’s great.
But if they’re cracked, and they need some seats and/or some guides installed........ do you really want to spend the money for that on castings that are already cracked?
I guess I’d(meaning you) have to assess the actual condition of the magnums you have on hand before I decided if they were a viable option or not.