Ever wonder what it looked like under the valve cover (ISM)? https://www.youtube.com/watch?v=iWyLWu_sEIM
Thats very interesting. Thank you for posting it. I hope my ISM is that clean. I wonder if those of us that have the tranny retarder have the "JAKE BRAKE" casting shown?
No, those are bolt on parts. With valve cover off on a coach with a non Jake engine the complete set of rocker arms are exposed making it a simple project to run the valves. The engines with the Jake option is a PITA to run the valves, like 3 times the work.
Mike
Have adjusted valves once or twice on a six cyl engine with it running,it can be done.