Triumph Repair: Clunking Noise in Rear of 78 Triumph Spitfire, wheel bearings, needle bearings

Question
There is clunking noise in the rear of my car that goes away under acceleration and deceleration. It seems to get worse when the car gets warmed up.

The clunking noise is still there when clutch is pushed in when moving forward and noise does not change when you put on the brakes.

I have replaced universal joints and inspected wheel bearings.

When you jack car up on jack stands and run it, you cannot hear the noise. The rear wheels seem to have to have the weight of the car on them so the noise appears.

Do you have any ideas of what else I should check.  

Answer
My question is how did you get the hubs off to inspect the wheel bearings? Very difficult to do even with the factory puller without destroying the hubs. I am sometimes able to isolate a noise by trying to determine if it is wheel speed noise or more rapid. Find a large parking lot and drive in circles to determine if when driving right hand circles or left hand circles makes the noise faster or slower in frequency. Since the wheel bearings are large needle bearings and a notch in the bearing hub could cause a noise with load and no noise without load.
let me know,
Howard