Adjusting valves

how do I adjust valves on 1990 5.0 ford.

You can’t.

Depending on the style of rocker arm, you can…They adjust the same way as a SB chevy. With the engine running, valve cover off, (yes, get ready for a big mess) loosen the rocker stud until it starts to click. Tighten it down SLOWLY until the clicking stops. Then slowly take it down 1.5 more turns. The engine will stumble until the lifter bleeds down and the valve completely closes…Repeat for all the valves. If it’s just ONE valve that’s making noise, make sure the rocker, rocker pivot, rocker stud and push-rod are all sound before you try to adjust it…You can’t adjust junk…

If you are trying to eliminate noise do not discount the possibility that the issue is not adjustment but a worn or defective part in the valve train. Your valve train has adjustment capability primairly for assembly purposes, that is it is not a service procedure.

thanks, getting at that back bolt on valve cover was challeging, however I did as instructed with success.

Exactly, and unless the top end has been apart adjusting the valves to cover up a noise is an attempt to whitewash the root cause of it; which you can expect to reappear.