Will this bore clean up, magnum head content too.

I would clean it up and run it as is.
I've seen a lot of scarier **** cleaned up and run without any problems.
I realize that there is a ''right'' way to do things and a ''good enough'' way to do things.
For your intended use, the ''good enough'' way would be good enough.
Clean it up and regasket it, but check the head and deck surfaces for straightness and correct if necessary.
The head gaskets failed for some reason.
JMHO...........