First jack up the rear of the car. Grab the wheel at 3 and 9 to see if there is play. Then at 12 and 6. If you have play at 12 and 6, then the chances are what your hearing is the wheel bearing. Support the car on jacks so you don't kill yourself.....see if there is play in the half shafts or the drive shafts. This would indicate U-joint issues. I had well over 100,000 on U-joints before they needed to be replaced. That doesn't mean you might not have a bad one.

 

Do as suggested above, 3 & 9 vs 12 & 6 play.

If the noise is varying more then I'd suspect bearing. If theres a hard shift/clunking into gear then that would point more to Joints.

If its the bearing, replace the joints at the same time or vice versa.

 

From the description of the sounds it makes during right hand turns would indicate that it is more likely the rear Wheel bearings or possibly a rear U-Joint.

Before you dive in, when was the differential fluid changed or checked last? On the older Corvettes with Posi-traction the differential will start chattering and other sounds from the lack of lubricant or the GM Posi Trac Additive.

The drive shaft joints can make noise when they start to fail. Frequently you can tell by the loud clack as the slack is taken up in the drive-line. If you grab the main driveshaft it should have a very limited amount of play and if it is bad you might get some noise by twisting it back and forth.

In my past experience the wheel bearings do indeed make noise when they start to wear out, kind of a whining from the one corner. It is hard for some of us to hear which one is making the noise without physically checking the wheels. My experience with axle U-joints is that they make more noise when being asked to work hard. Turning hard while accelerating should make some noise but not at the driveshaft joints.

Follow the great advice listed above by John and check those rear wheels thoroughly to be sure that you have no movement when pushing and pulling on that wheel. Since you are trying to find the problem you might want to do the same procedure at all four wheels By checking the rear wheel bearings you are starting in the right place. I had one of mine fail on a 1988 Coupe at 70,000 miles. It is not a fun part to replace so find a good mechanic.

The rear end of the C4 Corvettes have a lot of moving parts and many bushings to wear out. When moving the wheels around look and listen carefully. After 75,000 miles I ended up replacing virtually every bushing in the entire rear suspension.

When you get a chance take a good flashlight and look at the individual u-joints and look for any tell-tale signs of rust. If a joint dries out they make noise and wear out faster.

I wish you the best in finding the source of the noise, just don't "save" money on junk U-Joints. Be sure to buy quality joints from reputable companies. If you have more that the stock power in your car then you should consider upgrading to solid (Non-Grease-able, non-drilled) joints on the Axle half shafts.