Well, if we're going with that route, then all American warships should be able to equip themselves with 3"-50cals. These reached the prototype stage before the end of WW2, and the development was on the fast-track anyway. They became common fittings on a number of US warships in the decades that followed. A small number are still in service aboard US warships that were sold to foreign countries.
To give you an idea of how terrifyingly effective these guns were at AA: they are auto-loading, automatic-firing, auto-tracking, radar-directed 3" cannons firing VT-fuzed shells at a rate of 45-50 rounds per minute, all in the same size as a quad-Bofors-40mm package (albeit heavier). A single hit could stop-kill a kamikaze. And the best part? They came in dual turrets. (They also came in single-mount turrets.)
With a muzzle-velocity of 823 meters per second, a range of 13.3 kilometers, and a range-ceiling of over 30,000 feet, and a barrel life of 2,050 rounds (and magazines that carried over half that many rounds), these weapons were the be-all, end-all of WW2-era AA, and vastly better than anything but the 5"-38 DP, radar-directed turrets of American warships.
It's not just American Radar Master Race; it's American AA Master Race, too.