[vettestr]

You are fine and have not hurt the main bearings with a tight v-belt. We run roots blowers that are belt driven and no bearing harm is caused by the belt and I am talking about several hundred horse to turn the blower at full boost/RPM.
You would pull the v-belts apart before any damage would be done so do not worry about bending the crank or taking out the main bearings.Extra bearing wear on an alt. or water pump bearing would happen way before main bearing damage.