The thing with airplanes certified to older standards is that you do not necessarily have this modern transport aircraft capability of assured performance, when you can either stop or else go with an engine failure. That would be in any reasonably foreseeable case assuming that you operate within your performance limitations. With the Greasy Three there's often a little gap, but a very significant one, where you are probably going to come down with a thump if one of the donkeys quits. That gap lies between stopping safely and flying away.
There was one like that when I was working in Miami (which included a few hours as a right-seater on the DC-3), where a local hero lost one engine right after take-off, did a graceful pirouette, and crashed still abeam the runway. I understand that if that man's name had been Bob Hoover or Chuck Yeager then he might well have managed not to crash, but modern aircraft are certified for a pilot of normal ability to manage such a failure and get away with not crashing. Not the DC-3, however!
I bet that a CV-580 is longer than a CV-440. If so, that would give a longer arm for the rudder, no? That or else that the Allison engines are de-rated for takeoff.
Generally, you can not simply hang souped-up engines on an old twin engine airframe and be good to go. You get into certification problems that way because of Vmc and all that sort of thing. According to Wikipedia the Basler Turbo BT-67 uses PT-6A-67 engines that produce 1220 hp. The original Pratt & Whitney R-1830 Twin Wasp produces 1200 hp.
Where you often get the big gains through re-engining is with flat-rating, the extra thermal horsepower coming into play as you climb. Too, a turbo-prop is generally much more dependable than an old radial engine, because of design and age issues.
We used to get these guys coming up to the cockpit on the DC-3 as we were rumbling along at 3,500 feet, heading out to some island in the Bahamas. They would burble on about the romance, how this was "real flying" and all that hogwash, when I thought they should do a preflight on an R-1830 or R-1820 engine sometime and see how it leaks oil. (The joke with a radial is that if you see no oil leaks on the pre-flght, don't go flying; it is out of oil!) On a PT-6 I think it's one liter per ten hours, allowed oil consumption. On our DC-3 we would dump 5 gallons into each oil tank on turn-around out in the Bahamas when it was a long leg to Georgetown. Romantic, no so sure, but it certainly was sloppy!