Needing some advice please!!!

Hi, this is my first post, I am new here. I’ve been scratching my head on this subject for quite some time now and couldn’t seem to find the answer so I finally broke down and made a profile because I am a big Yamaha fan and I’m all the time wanting to do something different to them but enough of my yapping let’s skip to conclusion. Im needing some experienced advice on this one, I have an 07 big bear and I’ve been looking around for some good mods BC I love the ATV but I’m wanting some extra power to pull some big hills I’ve been eyeballing. I’ve been looking online for the past 4 months now and I’m seeing carb jet kits, high compression pistons, performance exhausts, performance cdi boxes, etc. I’ve been looking into a performance cam but all I’m finding is cams for big bears up to 06, I’m guessing they changed the heads on the 07s and up, maybe the oil journals are different on the older ones but I don’t want to rest ruining the engine on my daily rider and losing money so I thought I’d get some advice. if the heads are different or if there is no easier solutions, does anyone know if an older 400 head will fit my application? If I have to use an older head will I then be able to use the can I am looking at? Preferably a stage 2. Any advice would be appreciated, thanks!!!