They used to make two different CVD Kits, one which used the original
bearings and one that used the more common rear axle size bearings. Personally I would opt for the smaller axles/bigger bearings and go for the set that uses the rear axle bearings. They hold up much better to abuse than the kits original bearings. The only real difference in the kits are the axle diameters which allow you to use one bearing size versus the other. From what I have seen and personally ran my self, most if not all go to the rear axle bearing size when switching to front CVD's, for durability reasons, also helps with less spare bearings due to the fact that the rear hubs will use the same bearings.