Paint recomendations

I think for the look you want a single stage urethane will be the closest to the original acrylic enamel. What are your plans for painting the car? Remember the top coat will only be as durable as what is underneath it. This is a 50 year-old car and may have previous repaints over the original factory finish.

You may want to consider stripping it down to bare metal and starting over again with newer materials like epoxy primer, a 2K primer/surface, reseal with epoxy and then your top coat. One way to approach this would be one panel at a time.