53/67
I have a set of black diamond 53/67 gears. I know it is lower than what you wanted, but the top speed would only be 6 mph slower than the 55/65 gears. I think this would give a 700 the grunt on the bottom that the 800s have. I ran them on my 2007 M8 with a non reverse case and loved it. It was a tractor and top speed was still 78-80 mph.
