This is the one a lot of tutors use 
https://m.barnesandnoble.com/p/the-5-lb-book-of-act-practice-problems-manhattan-prep/1120686568/2660858947896?st=PLA&sid=BNB_ADL+Marketplace+Good+Used+Books±+Mobile+Low&sourceId=PLAGoNA&dpid=tdtve346c&2sid=Google_m&gclid=CjwKCAjw-ZvlBRBbEiwANw9UWoLKlMtwYruPdeGohm4OS-X9ndsfDgcnfNEWq11kO-6FD1H18FeS-xoCNqkQAvD_BwE
Does the fact that I am taking 5 IB classes and a dual credit this year, along with 6 IB classes next year bring up my chances at all?
Just wanted to mention that in 2017, the State of Michigan switched from using the ACT to using the SAT for the mandatory test given to high school juniors in April. So more UM applicants now submit the SAT than the ACT. (I doubt it matters which test is submitted, however.)
Also, around 15% of applicants submit scores for both tests. Presumably, this is to signal that a high score comes easily for the applicant.