[DAVID GAGNARD]

Diagnosing the problem by the photos is almost impossible in this case, breaking off the rocker studs indicate you have a valve train problem, find it and fix it, and you'll be fine.....I would leave things as they are now and contact the engine builder...not sure if there is any warranty or not at this point, but would definetly get with the builder if nothing else to find out about how the engine was built and the components used.....
Something ain't right under the valve covers...........

David