Removal of Ignition pack on rear of distributor? What type of heads do the machine screws have?

I believe there is a special tool used to remove these, it costs about $10 at Advance Auto Parts. It has the correct screw head as it is proprietary to Ford ignition modules. Also, the tool allows you to remove it in the vehicle without pulling the distributor.

make sure to mark the distributor if you pull it out, other wise the timing will be wrong if it doesn't go back the same way and you have to start over with #1 piston at top dead center i think