Yes a new radiator will for sure be a difference in cooling. Even if you get your original re-cored. It was explained to me awhile back that with age, and even though you may not be able to see it. The fins can start to pull away from the tubes which impedes the heat transfer. Not to mention some of them becoming plugged.
There is a member on here, Challengergary, who sells Champion aluminum radiators. If your not concerned about having the original, look into that option.