I have a stock unit from my F350 at home, if you can measure the compressed and extended length of the stock unit on your truck, I can compare it to the one I have at home. if they are the same, I would think anything that fits and F250/350 should work on the F450.

That said, I have a lightly used bilstein 5100 at home I'd sell cheap if you want to give it a go.

let me know

john