77 = Closed knuckles???
The high pinion improves your clearance, driveline angle, and driveline clearance. The reverse rotation (or high pinion axle) gears don't change the direction (rotation) of the axle, they place the rotating force of the pinion back on the drive side of the ring gear (like the rear 60 axle has) instead of on the coast side of the gear like the chevy and dodge front 60 axles have. So in that respect, the Ford RR axle is stronger than the Chevy/Dodge axle, but the Ford has a weaker Knuckle which is prone to breakage when high steer arms are used. They (Ford) also only have 5 smaller bolts that hold on the spindle compaired to the Chevy/Dodge that have 6 larger bolts. And the Hub is about 1/2 inch shorter on the Ford.
CR