Considering it is 20 years old it is most likely about time for an overhaul anyway. I would not be using 10w30 if it is a higher milage motor. I would probably try a 10w40 or 20w50 if you are not in a severely cold climate. Some of the better oil additives might also be worth a try.
You need a total de-sludge, Bucko. Probably your hydraulic lifters are full of varnish and sludge. Lifters are like little pumps that fill with oil to take up the slack in your valve train. If the oil won't circulate through them, they will loudly complain. Using thick oil will only make things worse, since it can't get by the goo, either. Go to a Mercury boat store and buy a can of "Power Tune". This is the best de-sludging agent around. Spray 2/3 can directly into your crankcase. Use the rest to clean the throttlr body plate and PCV valve and hoses. Drive the car for 2 days. The clicking should go away after about 20 minutes. The foaming action will dissolve most engine sludge, unless it's heavily crusted. By the second day, the combination of chemical and heat should have nearly rebuilt the inside of the crankcase. Change oil to Mobil One 0W-40. This will increase oil pressure and prevent cavitation and cold start-up problems. Good Luck!