Can I replace my draft inducer blower with a model of a slightly different speed?
I found this statement from the manufacture (Fasco) of my old and replacement part:


  The blower is designed to produce a certain amount of air-flow measured
  in CFM (cubic feet per minute). The airflow in some furnaces is needed to
  create a specific amount of vacuum at the vacuum tap mentioned above. If the
  replacement blower is not the exact one needed but “looks close,” it may
  produce a lesser vacuum at the vacuum tap. This may not allow the furnace to
  operate since the furnace will not think the induced draft blower is operating


So the answer is, it depends on if the replacement part will generate enough CFM to trigger the pressure switches.  In my case, the replacement is slightly more powerful (higher HP), but runs slightly slower (RPM). 

Happy to report that in my case, the new motor did indeed work correctly.