froze u-joint or bad shock?
 

got a 71 vette thats has sat outside for years. got it running and driving, new radial tires etc. when driving at 5-10 mph the right rear feels like the tire is out of round. anything faster and it goes away. tires are new and ive switched them side to side. its not a wheel/tire or a hub bearing. i can watch while someone drives the car slowly and it tracks straight. you can see the body go up and down on that side from the rear. only thing i can think of is it has ancient load leveler shocks on the back. the ones with the spring around them... could the axle joint be froze and cause this? the side that goes up and down is harder to push down on then the drivers side. anyone ever run into something like this? maybe a froze shock?

why not pull the shocks and test drive it at 5-10 mph?

Or just replace them. Sounds like they're junk anyway.

sounds like a bad shock. especially if it is sticking down at low speeds putting sustained geometry angle on that side.

you may also find your leaf springs are weak, someone may have added those spring shocks to compensate at some point.

Frozen u joints usually make a lot of noise

no noise