[xj_man_646]

Stock for stock there is no question. Who doesn't upgrade to 35 spline outers at least on a KP 60?

The 05+ F250/350 axle will accept OEM 1550 shafts available for the F550 I believe. The large spread on the ball joints increases the strength, and they do not have the weak knuckles that the old Ford axles have. I believe they also have larger and thicker axle tubes.

The real fun begins once you start spending money. RCV makes a 'big bell' shaft that eliminates the lock out / drive flange component and engages the entire hub of the UBH...can't recall if this requires aftermarket knuckles or not.