1990 Chevy Blazer steering has a lot of slack

1990 Chevy Blazer 350 mileage: 123,000. We have had this vehicle for about five years now. It has a new motor in it now and it runs good. My question is about the steering. It has a lot of slack in the steering and I wonder if there is an easy solution to tightening it. It probably has at least 6 or 8 inches of play in the steering wheel before it reacts. This is sort of dangerous. I would like to try to tighten it myself if I can. Can you help me?