What would you do?

If this car is just going to be a driver, and you want quiet, leave it alone. It's not going to run any better with duals and will probably change your tune, your fuel mileage will drop. The car will be louder and probably have a drone. How do I know this, it was done to my '72, should have left it alone. Make sure that your heat riser is free and working in the pass side manifold. If it is truly just a driver, plan A. Otherwise you have the other posted advice. Just saw the why of all of this on Engine Masters, very interesting what actually works best best.