Depends on exactly what you need. The housings themselves are the exact same size, but the axles are 1.25" longer, making it 2.5" wider overall. Some people have put the axles and brakes on their car in stock form, but it sticks out too far even with 8" wide wheels IMO. I have the Mark VII brake setup that is modified to use the shorter Ranger/ Aerostar axles (same length as the 4 lug Fox ones) and it works great. See http://home.pacbell.net/black306/tech/reardisc.html for more info.