05 pred 500 engine question

Brand new to the forum. I’ve got a 05 pred 500 completely stock. Does anyone know a place or a website I can buy a new engine or a top end rebuild kit? I’ve searched and can’t find anything. Also any info that anyone’s done to theirs as far as a big bore kit etc and prices what not. Or what motors will swap into this with little to no mods. I’ve never tore into a 4 wheeler but I am an mechanic and have all the tools. Thanks in advance