How do I find and where is the pitcock or drain valve on 1997 Z 71 Chev
1/2 ton 350 c for radiator drain?

Should be on the side under the tranny lines. one side or the other. If you can't find it, just pull the lower rad hose off. Have a big bucket ready tho...

The valve should be just on the under side of the radiator. Not sure exactly, perhaps LB's advice is more helpful, but it really shouldn't be too hard to find it. Are you aware what it looks like or is it just hard to find?