Thanks for your comments Ed & John,
I had in mind to keep the Riviera in it's original configuration,not to do a "frame off restoration" like my son did with has 1966 Skylark.
The Riviera was bought for it's engine,but it runs,shifts,brakes and has no rust so my intention was to use it as a daily driver.Certainly not to flip it!
However,the interior needs to be re-upholstered,all weatherstripping is brittle and the tires are gone.Upholstery is still available according Ed's information.
So it might be possible to put it back on the road for let's say 3000-5000 USD?