I second that, it's difficult to get an idea of the HP a 440 puts out because the torque is so intense. When you have 400+ lb-ft basically off idle all the way to even just 4000 RPM you won't be able to tell if it actually puts out 350, 375, or 400 HP unless you're doing actual timed runs. From my experience it's one of those engines that even the lowest-performance smogger piece of "junk" 440 is a torque monster with impressive performance. 250 HP doesn't sound like much but my cousin's 1972 440 Polara would lift the left front fender about 4 inches when you stepped on the gas from all the torque, no way a V6 Toyota Camry with 250 HP could do the same thing.
Also like @451Cuda said even the Hi-Perf engines were in a very mild state of tune from the factory and they have so much displacement that the power increases you get from upgrades are HUGE. Just a cam swap with all other factory parts will put it over 450 HP.