Starter help!

Ok so I was told to run a 98 Celica GT starter with my ST205 swap. I purchased the starter from toyota, installed it then tried starting it and all I heard was the gear spinning. So I pulled it back out and checked to make sure the solenoid was working and the gear was coming out, which it was. Next I checked the flywheel teeth and those are good. Did I get the wrong starter? please help. Thank you.

Check to make sure you're getting the correct voltage out of the starter lines. If there's any drop or resistance it may not be enough to turn her over. You could always try bypassing the starter lines and straight wiring it from the battery. Not a fun test (make SURE you're in NEUTRAL!) without help to see if it will turn over, thus eliminating some other possible hiccups.
*edit*
I forgot to mention that you will probably get sparks from trying to hook up a connection so I usually will wire from the starter line (pulling out the other connection) and striking it on the battery post. You will get sparks so be forewarned (have extinguisher ready, wear rubber sole shoes and no flammable liquids or metal on your hands/wrist).