bornriding - The Carrier spec shows the same wheel for both motors (10x6).
eisenberg - I am not a motor expert so I would wait to see replies from some others on this site that may know more about motors before changing anything just yet. The Carrier spec should be correct unless there is a typo in the documentation. I also would wait on changing duct sizes until you decide what you are going to do about the CFM issue.
How high are your ceiling registers and is the return high or low?