Chrysler Repair: 1991 Caravan 3.0 timing belt, interference engine, cam shaft

Question
Maintenance manuals state to replace the Mitsubishi 3.0 timing belt at 60k.  I have 80k on the orginal belt.  I understand this is a NON - interference engine and while a failed belt may cause incovience, it won't destroy the engine ... True?

What is the actual failure rate for these belts?  I am inclined to run it to failure as I have been quoted $500 - $700 to replace it and the water pump.

I replaced the original serpentine belt.  It was cracked, but intact.

Your input please.  Thanks!  ~ Loren  

Answer
On the timing belt, correct it is non-interference. I can't give you any data on the average belt life or the point where they begin to fail or when they are virtually all going to have failed ( e.g. the failure distribution). But many do go to 100,000 miles. You can inspect the belt quite easily: remove one or both of the round discs at the top front of each cylinder bank, held in place by 3 bolts, and you will see the belt wrapped around the cam shaft pulley.
You then can tweek the ignition key to crank the engine a bit at a time and thus check the condition of the belt all the way around. If you see no separations or rounding of the teeth or cracking of the rubber then I see no reason to change it out. Maybe the ideal approach is to wait until either the belt or the water pump fails, then replece both at that point. So just keep an eye on it from time to time so you aren't stranded far from home.
Roland