so as i was getting down to removing the heads on this 95 D1 3.9 and on the right side i found what look like to be shims under the rocker shaft where it bolts to the head. they may be no thicker than a .012 feeler gauge. there wasnt any on the other side. i found no reference to them in the repair manual(RAVE). these heads have been off before by another shop. So i'm not sure if they even belong there. they were not on the left side and the truck ran fine untill the overheating and then the blown head gasket. so i am not sure what purpose they could have served. anybody familiar with this set up?

The shims are used to set valve lash (er, lifter preload, and thus valve lash) on engines that do not allow for adjustment in other ways.

Some folks will mill the shaft supports to change the preload, others (like me) don't worry too much about it. However, if they were there when you tore it down, put them back when you put it back together

Peace,
Paul

thanks mannnnn!