King shocks not working

Well OP, if the fortuner has a completely different trailing arm and spring set up, disregard anything I posted above. My apologies.

 

Too long is only an issue if they compress into themselves much like too short is only applicable when they unseat at droop... Otherwise spring rate is pretty obvious when it's wrong because long springs need lower rates than short ones for a given ride height. If you install a 600# spring that's 2" too long for the target you'd see a fair bit of extra lift.

This is why tuning is important because a stiffer short spring and softer long spring can fit the same application but they will require significantly different valving.