It is tough to wake up a flathead much without getting into a fair amount of work on the block and valve train and induction/exhaust systems. The new heads by themselves won't make it run any better unless the old heads are broken, and a new carb, even though a Stromberg 97 might flow a bit more air than the stocker, it won't do much in terms of real performance. Now, in the area of looks, yeah, the heads will look great, and if you really clean the whole thing up and paint it, put some new plug wires on it, a few chrome accessories, and a set of dual exhausts, it will run well, an look and sound good doing it; a nice cruiser.