I have a 1978 Datsun 280Z with original paint that is dull and showing many surface scratches - is this clearcoat paint and what can I do to try and save it?

right about the lack of clear coat- that's an old classic ya got there- bad clear coat looks like "peeling" skin- and it's impossible to fix- if your Z car has factory paint, try "Liquid Glass" easy to use and gets rid of the oxidation fast- oooooh! shiny! pretty!

As silly as this sounds, used motor oil. Wash car car thoughly let dry you can use a buffer....... messy. Hand application works best apply in direct hot sun, as the heat opens the pores in the paint. You will need to let oil soak into paint let sit till it paint dulls again wash w a good detergent repeat till desired depth of color is restored on final wash well wax in a warm place out of derect sun. This is tried and trued. Cutting and buffing will thin the original finish thus losing classic apperance. Paint like skin dries and sheds the oil is moisturizer for paint. This method is for solid colors w no clear coat. Cars prior to 1986. Good luck

A few days may be needed between applications