He would lose a little turning to the left because of the steering arm ackerman angle. The arm is bent slightly towards the driver side, thus when steering to the left the arm is already partially pointed towards the gearbox. When turning to the right the arm has to pass over the centerline through it's travel and then start pointing away from the gearbox, thus creating more travel to the right. This has nothing to do with the axle being moved forward. All angled steering arms will exhibit this characteristic.
As far as the axle being forward 8", I come up with 4" broke down like this:
Stock 23.5" front eye to pin (yes, front springs are actually 47" eye to eye with a centered pin) minus Ford 25" front eye to pin for 1.5" back, then front mount moved forward 4" to total 2.5" forward, then zero rate 1.5" forward for a total of 4" forward. What did I miss?
Travis