Where should i run the ground wires to?

well when i changed the battery cables, i somehow broke the bolt securing the ground cables to the motor, can anybody here tell me a good solid place to ground the battery cable ?

Motor mount, cover bolt, v cover, starter cover,

You can always remove the broken bolt and mount the ground to the engine cases as the original designers thought best. If you don't want to do that, there are bolts on the battery box mount brackets that will work. Make sure that the ground touches metal and not paint.