will a 2002 Polaris Pro X 600 air box fit on a 04 pro x 440 with a 700 engine?

NO, 600 is a small block and the 700 is a big block.... the 2002 air box is a pita to get the carb rack out , the 2003 and new airbox is much nicer to install ....in the end you will be much happer ! it is poss to take a 2002 small block airbox and replace the black pannel where the carbs fit in to make it fit a big block BUT depending on what steering shaft you 440 chassi has it may not work.

I was wrong ...the 2002 600 prox and 2003 ~2004 prox 600~800 all use the same airbox , you should be fine. Sorry for the bad info.