I'd be surprised to see any significant wear in the steering gearbox with only 50k miles. We have 52k on ours and the box is tight. First check the wheel alignment both front and rear, shock absorbers, wheel bearings, wheel balance, tire pressure and measure tread wear all across the tread for even wear. Also inspect that rag joint as Bill said above. If all is well there are two adjustments you can make to the steering gear. Both require disconnecting the battery, removing the horn button and removing the pitman arm. It is necessary to mark the relation of the pitman arm to the pitman shaft before removing it so you can get it back on where it was. You will need a pitman arm puller, a lbs/in torque wrench with a range not exceeding 50 lbs/in and a socket that fits the steering shaft nut under the horn button.
The step by step procedure and torque readings are in the 1981 Corvette shop manual on page 3B2-4. You can't get an accurate torque reading with the pitman arm installed. Keep in mind that you need to adjust the thrust bearing preload first to 5-8 in. lbs. and then adjust over center lash to 4-10 in. lbs in excess of the bearing preload. So if your trust bearing preload is torqued at 6 in. lbs., for example, then the over center would be torqued to 10-16 in. lbs.
If you determine that you need to adjust the steering gear but can't find or don't have a factory shop manual I will try to scan the page for you. I would check all of the other things I listed first though.
Tom