I'd bout be tempted to get a new bolt & torque it in & try it but with it bleeding compression between the 2 cyls as you originally stated I think it will have to come apart but I think I'd try it for a day just to see . Wait & see what others say. Dont forget to pull the hex block drain plug on that side as draining the rad only lowers the coolant to the level of the lower block front 1&1/8" main coolant hole on that side & it will spill coolant out of the outer deck holes which are below that level into the cyls when you pull the head