After I looked at how involved it was going to be to get that head out I said "Huh uh." So I decided to grind the screwhead off and do without it. Missing one of 8 wasn't going to hurt. So I grabbed the flex-shaft grinding tool, one of the few Craftsman power tools I own, and started grinding when I realized I should try to grind a flat spot on this large allen screwhead and tap it out with a punch.
I ground a nice one and took a 3/16" machinist flat punch and tapped that sucker right loose!
Now that sure felt good. Back in business.
This is the first time I have ever posted a problem, said forget it, then solved it.