I’m currently a rising junior who is interested in Pomona, Amherst college, or Dartmouth college. I heard from many people, including teachers that although colleges states officially that they treat SAT and ACT equally but western and eastern coast colleges actually do have preference of SAT, personally. Do they really prefer SAT over ACT personally?
Colleges, except one, do not have preference and either test is fine . The one: California Polytechnic at San Luis Obispo, one of those western colleges the rumor mongers undoubtedly include in those that must prefer the SAT. It states a preference for the ACT. The one thing to consider is the following: if in fact all those eastern or western colleges which state they have no preference really prefer the SAT and look down on those that submit ACT, then the only conclusion that actually can be reached is that those colleges are all bold-faced liars, a doubtful proposition, which if true means none of them can be trusted on anything they say about admissions and you should thus avoid applying to any of them.
All colleges accept both. You should submit the scores that are higher. You can find a SAT ACT conversion chart online.