The big thing about a repower is it absolutely kills the resale value . Plus you loose lift capacity those Wisconsin engines are heavy also the hydraulic pump is going to need to be driven somehow. I repowered a 500 with a 27 horse Briggs it worked out well an I use it to feed my firewood processer . If I sell it I would be hard pressed to get 3000 . I rebuild 610s with rebuilt Wisconsin engines' . Look around you should be able to find a rebuilt engine for not much more than 2000 with a good core
I don't remember the website, but there is a company here in the Midwest that sells repower kits to replace those. They have supposedly everything you need to convert it. Some of those take a special crank to adapt. I haven't done it so I can't say for sure. If I can find them I will post a link for you