I just put taller rear end gears (3.25 versus 3.78) in my '41 coupe to keep up with Interstate traffic on the longer trips. That brings my sweet spot of 2700 rpm up from 56 mph to 65 mph. Nice.
But for traveling at those speeds, I wanted better brakes. I changed the front from stock Lockheed to Bendix (Lincoln) self-energizing brakes. Fortunately my drums were good so the cost of parts from MT was only $400. Stopping power per pedal pressure is substantially improved, and should get better as the new shoes arc themselves to the drums.
My wife's '34 pickup has disc brakes in front. They work great, but without power boost they also take substantial pedal pressure, even in that light weight vehicle.
With a tie in performance, I would go with the cheaper, simpler drum brake upgrade.
One post said .060 as the limit oversize for turning drums, but I have also heard .080. If you go over that far you should probably have the snoes professionally arced, versus wearing them in on the road.