Impact drivers are your friend in removing clutch head screws. Tighten them just enough to make them move and break the bond.
I used my pneumatic hammer with a clutch head tip welded on. I also added a screwdriver welded to it as a handle to help turn the tip.

Wayne
1938 1-Ton Farm Truck
Stovebolt Gallery Forums
1989 Silverado
1996 Mustang GT convertible
When I die, I hope she doesn't sell everything for what I told her I paid for it!