Sapper,
Coast High Performance and PAW make stroker kits for the 351W. See
www.coasthigh.com or
www.pawinc.com for details.
Also see the November 2000 issue of "Muscle Mustangs and Fast Fords" (or something to that effect) for an article on putting Air Flow Researce 185 heads on a stroked 351W. With a Comp Cam, it made over 500 hp. I saw the article on Westech Performances website.
Brad