I installed a 6.9 C6 inplace of a 5.8/C6 in a 88 Bronco EB and it worked excellent, I even used the stock coils(a new set of aftermarket cargo coils whatever that means) and the front suspension held up just fine. The ball joints and steering are very close to a F250 2wd . I did upgrade the rearend to a 1986 9" posi out of a supercab, but other than that is was stock Bronco. If you're only building a daily driver, and not a plow or offroad truck, the stock axles will hold up fine. All mounts were from F250, including rad/rad support. The Bronco handled and rode well w/front/rear sway bars, and the only thing I would probably done different would be a set of rear supplemental air bags and maybe the 3.00 instead of the 3.50 gears I had.
Even the fuel tank and lines were easy because the fuel injection already had a return system. Don't let the Nay sayers discourage you, it a very nice convert when you're done and can look stock if you take your time.
I sold my 88 for $9500 CAN in May 01 and the guy didn't even blink at the price.