How many MCAT practice exams are out there?

i cant find an answer to this. Has AAMCAS only released 3 practice full length exams EVER? also what is the difference between the AAMCAS Section Bank and the Official MCAT guide question pack? i do have access to both but i haven't "started" them. are they timed exams? what is the difference? just beginning MCAT studying today; any tips would be appreciated!
Source: Student Doctor Network - Category: Universities & Medical Training Authors: Source Type: forums