I am not in the USA, but I am should be able to look for other screwdrivers here in the UK. I already have one quite big one, but I think it is still way too small for this purpose.
How big is it? For ridiculously large flat-blade screws, look at "drag link socket"s.For just getting extreme amounts of torque, use a bit on a ratchet, rather than on a screwdriver handle.
