not sure what size plug you need, plus this answer might be a lil late, but try vividracing...
http://www.vividracing.com/catalog/blow-off-valves-accessories-c-4266_4267_5345.html
actually i believe that extra (top) bung is for the valve cover line. if you are using an intake (some short ram models) that do not have that, then you would need to use that part of the TIP.