Here is what I found in the manuals I have . Starting at the No. 4 cylinder , loosen the right valve rocker arm shaft support bolts in sequence , two turns at a time . After the bolts are all loosened , remove the valve rocker arm shaft assembly and the oil baffle plate . Starting at No. 5 cylinder, follow the same procedure on the left valve rocker arm shaft support bolts . THIS PROCEDURE MUST BE FOLLOWED TO AVOID DAMAGE TO THE VALVE MECHANISM .
Firing order numbers should be on top of your manifold . Hopefully this helps , keep us informed . Thanks Wayne