Welcome to DC. Enjoy the ride. I don't know if the noise is axle/bearing noise or differential noise but if it was me I
d reach out to gtr1999 on this site through a PM. He is the most knowledgeable person I know about on Vette rear ends. He is honest and a stand up guy. He'll treat you right and won't try and rip you off
Thank you Torch.
For the noise in the right rear it may be from several areas.
I would get the car in the air and check the bearings by checking the amount of rock in the wheels at 6&12 and 3&9, there shouldn't be much but if you do feel something, remove the wheel and check it again without the leverage of the wheel/tire.
If there is play at 6&12 then look at the amount of movenment the 1/2 shaft has going in/out of the differential. There shouldn't be much but if the diff is original and has 40K+ miles you may see 020-030- or more" endplay and that may be one issue but probably not the noise issue you heard unless the axle worn down enough to hit the diff housing - then you have a problem.
If you have play at 3 & 9 then look at the wheel bearings as possibly going bad. Grab a wheel stud and see if you can push/pull on it and if you feel movement. Check to see if the rotors still have rivets in them, indicating original untouched arms. If the rivets are gone then that may just mean someone replaced them or the parking brakes.
Rotate the rotor and listen for any metal on metal, maybe the parking brakes are original and broken dragging on the inside of the rotor.
Make sure the shims are in place and tight in the frame pocket where the arm bolts in.
Check the u-joints for play or rust trails. There should be no play when turning them.
If you have any questions just call my shop line 203 439 8020 and I can go over them with you.
Good luck, it's just a problem to deal with not the end of the world. Owning an old corvette requires maintenance and repairing the bad work of previous people. That's what I do every day.
Gary