Originally Posted by kingoddball
How could timing or valves be checked?
Best thing to do is get the Toyota factory service manual for that engine and year. From there, it will tell you the procedure to check timing.
Usually eBay's the way to purchase the service manuals of that era. The other option is a Haynes or Chilton's repair manual.
Regarding the valves, without having to remove the head to visually check the valves, you could do a compression test or a leak-down test. Those two tests will tell you the sealing ability of the combustion chambers.