Timbersled Strut Fitment

It should work. If you go on timbersleds website they have a search tool where you can put in your track kit, old bike, and new bike, and it will say if you need any different parts to make it all fit. It says you shouldn't need any. There is also a fitment chart on their website. It shows all the specific bushing required for each bike and the strut length. You will need a different set of upper strut bushings, they should have come with your 500 fit kit.

It calls for the same strut P/N in both install kits. So I would imagine you would be able to adjust it from the 14 3/16" req'd for the 500 to the 13" req'd for the 450 xc-f. I have a 2014 500 exc which is the same as xc-w and it looks like the strut could be shortened at least 2" so you should be fine as long as you have those different upper bushings.