Yep, that would be the C6, there does not seem to be a whole lot of C6s in trucks this age. Mine is a '94 and that was the last year Ford put them in trucks. I have heard rumors that the C6 was available in certain fleet/special order vehicles until '96 but I am not positive.

The C6 is an extremely tough transmission and they hold up real well. My grandfather towed a 10,000 pound trailer with my truck and my tranny is great. With the shiftkit and adjustable modulator mine performs great. I could not be more happy with it, overdrive would be nice, but I just limit my highway cruising speed to 55 mph and I get about 13 or 14 mpg and it even got 15 once. Having 4.10 gears is part of the limiting factor in my cruising speed, if you have higher gears you should be able to go faster, but high speeds are extremely detrimental to your mileage when you don't have overdrive. Flat out my truck will only go about 85.