Plus, as it's been said, you cannot fit a spacer, sprocket, ANSI 35 chain, and bolts all in there.
If you're just trying to prototype mounting options, here's one that seems to have worked for another team. The brackets are simply shelf cross members you can buy at the hardware store:
http://www.youtube.com/user/SteveJes.../1/UQQ67SB8Acc
As another poster said, I would strongly suggest working up some CAD for a sturdy mounting system of your own design, as opposed to planning on using the KOP brackets or something similar to the YouTube video...