Oh it's like Alpacas and Emus and Ostriches. Only the stupid get conned thinking its going to be the next big "investment". That car really needs to go into a museum. They hold no real value other than as a piece of Australian history.
Same will go for all the 70's and 60's hero cars ultimately.
They make no money for you. If you are very lucky they may retain the original purchase value(that's if you don't have to spend the same amount restoring them).
Stop trying to make them into money earners and just sink the dollars into them to fulfill your own enjoyment.