I see Kakuzu winning this to be honest. He's faster than Kakashi so there's a chance he could end it quickly, and if Deidara takes to the skies then Kakuzu can just release the masks. With 4 of them on his tail Deidara is going to have a tough time, and Kakuzu could force him to the ground with them. His iron skin would give him a good defense against the bombs as well, C2 or higher would likely be needed to do any damage at all.
Not to mention, Kakuzu has got an extra few decades' worth of experience on Deidara.