There are different p/n rocker arms based on engine # and/or camshaft.


6150550201 All 617.910, To 617.912-077421
6160500333 From 617.912-077422

Another site say 50201 is for "models with original non-hardened camshaft 6160510201 or 6170510001. Limited availability"

Did you possibly get the wrong part for the new camshaft