Wow. I am in the exact same situation....except my Riviera is a '64.
Mine used to belong to my Great Aunt and my Dad bought it several years after she couldn't drive anymore. When he died, my Mom gave me the car.
It is in my garage with 31k miles on it ( I believe original ?). There is some rust, some dings, and indications of some previous touchup that doesn't match real well.
I'm torn between the factory original resto, or like a '65 spotted at the Hard Rock show after SEMA.....LS1 / 4l60e combo.
Hmmmmmm.......I'll be listening to this thread.
Pictures of my 1964 Riviera
Randy