ACT and SAT - how different are they preparation wise?

<p>I have taken the SAT once (May) and will retake it again this October. I am taking the ACT this Saturday.</p>

<p>I have not studied much for the ACT, but I have studied plenty for the SAT. Will I be fine for the ACT(regardless of the Science section as I know the SAT does not have a Science) or will I have to do more "ACT Prep." before the test? </p>

<p>Anyways, I am planning on retaking the ACT in October (along with the SAST) unless I get a 30+ this Saturday.</p>