Erratic idle
Time to change your timing set.
You had better believe that slop in your timing chain will cause an erratic idle. If the timing changes while the engine is running, the idle speed will change. If your Cleveland is still stock, the chances are that the nylon covering on the timing gear has cracked and broken, and just that alone will cause a great degree of excessive play in the timing chain. The real problem is all those little nylon bits and pieces are now in your oil pan, getting sucked into the inlet screen of your oil pump. Do you see where this can lead?
Time to change your timing set.
If there are many pieces broken off the cam gear, you're going to have to either drop your oil pan, or otherwise flush all of those naughty bits out.
Have I mentioned that you really need to change your timing set? :1poke:
Cougrrcj