You need a pulley twice the size of the grizzly motor pulley. You may have to make a new guard for the pulley and belt. You may loose a little torque, but I don't think so.
Those motors are explosion proof so you will never have to worry about dust getting into your motor.
Those motors are probably worth 2 - 3 times the asking price. A great deal.
Only thing to be sure of is the mount. Needs to be the same mount as the saw.