I understand that not all auto mechanics are familiar with our turbo 6 engines but any machine shop should be able to take care of the head refresh, right?This may have been slowly happing before you did the 87 ecm upgrade. I would have them check the spring pressures while you're there.
I had the injectors serviced when I replaced my intake gasket, prior to getting the car on the road full time. I can have them flow tested just in case.While you're at it you should have your injectors cleaned. It's possible they are clogged and caused the rough running etc and lead to the lean out.
Good copy: New timing set on my shelf, just waiting on the damper from RA. Oil slinger on order. The lifters & cam (lifter to cam) contact surfaces show no pitting or signs of distress. Will reuse rocker assembly (new buttons?), pushrods and lifters.Clean off one of the tops of the pistons and find out if its STD or over bore. Put the slinger back on...it's there for a reason. I'd go with a new timing chain set with the wear I'm seeing.