If you can't make your own
Custom Battery Cables F350 cables
If you want to make your own buy SGT wire ( not welding cable like some people think, the housing is NOT suitable and the cables will fail in a short time)
I made my own with 2/0 for the crossover, 3/0 for the start, and 2/0 for the grounds, I also have some extra that I'm going to go fromt he alternator to the driver's side batter, I've been told we can't just remove the factory wire and upgrade like with other vehicles.
And Military style terminals is best. I suggest ( so does that website) you crimp, not solder, soldering isn't as good.
This was the first generation.
Then we had 4 -40*C days in a row and my Interstates both cracked... So here is the second generation.
That's a group 31 battery, 975CCA, that only costs a whopping 97$ ( for comparison in Canada interstates are about 180 a piece for the 850CCA). The batteries required some modification, but damn they were worth it.