question about hole in my head?

[hi4y]

Hello I am the proud new owner of an 87 2x4 auto on the island of hawaii. Mahala for all the information here without which my van would not be running.
It started running really ruff and today when poking around I found an empty threaded hole alone the valve cover behind the intake looking in from drivers door.

Not sure how long it has been like this and if anyone can tell me what goes there and what size it is (;) I would really appreciate it!

[hi4y]

[hi4y]

In fact, I can see there is another threaded hole barly visible in the picture further to the rear of the engine.....I don't like this one bit at all a bit of exhaust escapes and I wonder if its apart of egr that was hacked into?

[hi4y]

[timsrv]

Those are just blind threaded holes. Not sure why they're there, but they don't go anywhere and are of no concern. Perhaps Toyota used them to hold the head during manufacturing? Tim

[hi4y]

What an appropriate new owner question!
Thanks for resting my worry.