the original clutch head screws are slightly hour glass shaped sockets - like these - there are screwdrivers made to fit, available at most vendors, and from a lot of tool places, like SnapOn and usually NAPA
"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir "When we tug a single thing on an old truck, we find it falls off" ~ me Some TF series details & TF heater pics