What kind of noise or "signs" would tell me that my timing chain is going bad??

thanks

You can measure it, turn engine to TDC or BDC, doesn't matter, just make sure the timing mark is showing on the timing ticks where you set the ignition timing, remove the distributor cap, and turn the engine one direction till the engine is at the 0 degrees TDC/BDC mark, then turn crank other way till rotor just starts to turn, and note the difference in degrees. If it is getting more than 4 degrees, then you are probably due a fresh chain. I don't like to see even 2 degrees, but that is pretty extreme too. I like to advance the cam 2-4 degrees to take up the timing chain slack. Then once the chain stretches, it will go back to factory desired cam timing (cam timing is NOT the same as ignition timing).

A really slack chain will make slapping noises and have less low end power and better upper rpm power (on the order of 500 rpm or so). Buick eliminated the slapping noises with a tensioner, most OHC engines use one too.