Not a 440, but I saw an article in I believe Engine Masters Mag about a year ago where they assembled a RR spec 383, and came up with exactly 335 hp!

Horsepower ratings are sooooo subjective though. Seems that Ma Mopar underrated back in the day, or rated at low RPM's for some reason. I.E.: Sure, a 67 solid cam dual quad hemi made 425 hp at 4200 RPM's (published)... BUT, what was it making at 6200 RPM??? (Likely in the 475 range). Chebbie ratings were always impressive, but the cars didn't go any faster than mopars with substantially less advertised HP. Everyone raves about the LS-6 450 horse 454, but where is it at the drag strip?, likely struggling to keep up with a 375-horse 440. Buick GS 455's were rated at 360 horse, but they would flat blister at the track! The only thing that really matters is: WHAT DOES THE TIME SLIP SAY?