I've never seen anyone not able to run a stock front shaft. The only exception to this is occasionally the shaft needs to be shortened because it bottoms out on droop with a tall lift and short arms. The reason the front is OK verses the rear is because the front axle moves rearward as it droops, including the lift. An 8" lift can produce a 1" shorter wheelbase because the axle is rearward because of the steeper angle of the arms, so even though the lift is higher, the front shaft is OK.