On the street the 440s low end power is killer but it really is a heavy powerplant and the handling will suffer. That being said the main thing I would change on the car in that swap are the torsion bars to handle the extra weight (a little reinforcement with a mig around the shear panels, radiator support and cowl areas wouldn't be a bad idea either)
As far as value goes since the orginal 340 is gone the 440 should add some value in an online auction. I don't know if the value added would be more then cost of building the 440 though and you would have to buy a new radiator, tranny or bellhousing, headers and other little stuff.
Maybe an easier way to improve power and handling is to lighten the car up a bit. A fiberglass hood, headers, aluminum intake, lightweight wheels ect and some track tuning should get you into the 12s. Unless you already have that stuff....
