Typically all of the bolts on the timing cover are the same for a 5vz. IF you have a shorter one and you didn't notice where it was while taking it apart do like the pros do and put the short one in first. If it was short for a reason from the factory it shouldn't reach in the other holes. If it...
You wouldn't happen to be running load range E tires would you. I've heard that with their stiff sidewalls and extra weight they will beat up the driver on our smaller trucks. Just a thought.
JC
Would love to hear more on what you find alanflies. Was considering the TTBOSSRES-9602 or a set of Kings for the 4Runner. Did you adjust the setting on the front reservoirs so that it was the softest?
JC