i found a D60 closed knuckle, and i think its drum brakes, havent seen pics yet but its from a M715 (kaiser), and they usually were drum brakes. 1- is closed weaker? can it be easily swapped to open? 2- can it be swapped to disk brakes easily? 3- is it worth $600.00 with a D70? it has 6x5on? (oddball) bolt pattern, can that be swapped also?