Denny,
I use flat-head blades all the time with clutch-head bolts, even though I have various sets of clutch head drivers and bit-heads.
The interesting thing about clutch heads is the self-centering aspect of the head. This characteristic is like a Phillips head, but the clutch head has a much more positive "feel" and a stronger "grip" than a Phillips. Good for efficient assembly lines - human assemblers when our trucks were built.
By the way, I get a kick out of people who say they dislike the clutch head bolts because they rust so badly and are so hard to remove. That is foolishness - any steel bolt that sits on our old trucks for 40-70 years is going to be quite rusted (unless the truck has lived in an arid environment). It just so happens that most of our bolt heads are clutch head; they are rusted; they are therefore hard to remove. Do not blame this on the clutch head.
Tim
