December 24th, 2015.
It has been my observation that blower motors (or any electric motor for that fact) are often designed for an intended use /application. If the motor is intended to be mounted vertically, the output shaft will run on ball bearings or roller bearings orientated to take that particular load, if horizontal, both the output and tailshaft bearings will be set up to take thrust horizontally and also to bear the weight of the armature. To set a motor designed for horizontal use up vertically, well, the results should be quite interesting over time, please do report back on what luck you are having!
Have a Happy and Safe Holiday Season and a Prosperous New Year's!