Can the plastic vapor tank from an early z be replaced by one of the later metal tanks? If so, how hard is to make the swap?

Thanks,

Bob

The swap itself is easy.

The problems are the fragile, brittle interior panels that need to be removed to gain access. Also, you will need a different rear interior quarter panel because the plastic vapor tanks are shaped differently and are smaller than the metal tanks. Thus your original interior panel will not fit over the later metal vapor tank.