Dan,
Thanks for the advice. I did check the engine number (GM 3835517 15) matches top and bottom of engine. The interesting thing about the two different rocker arms is they are stamped with 82. other ones have different stamps so it appears they were same rocker arm...perhaps a mistake by a past repair?
Jerry,
I would rather spend days/weeks tearing things apart and fixing it right than fix it multiple times so I am certainly going to dig in to cause before I start testing with new parts installed.
