There's only going to be ONE numbers matching engine for your car. Store the matching 383, build the 440 and run the "H" out of it without having to worry. If you build the 383 you'll always have that little voice in the back of your head (I have 3 or 4) telling you to ease off the throttle. If you throw a rod through that 383 it's gone, if you throw a rod through the 440 just find another and go at it again.