Hey Ed, thanks for the info, it's a big help. I was more wondering about tire size, not wheel size. For wheels, I was thinking about getting some medium duty 20" steel wheels and getting the bolt pattern redrilled (I've had that done before), but then I might just stay with the 16" I have already. When I try to sketch things up, the stock tires look really big. So I was wondering if I'm using the right size, or my scaling is way off. I haven't checked how the cab will look on the c3500 chassis yet. The COE cab is a TON shorter than I thought, so I'm in the process of trying to do the aforementioned sketch before I start hacking things.