Send both SAT and ACT or leave out lower SAT score?

I scored 1850 on the SAT and 29 on the ACT. My ACT score converts to a higher SAT score (by 100 points or so), so should I just send that to colleges and leave out my SAT score? Or is it a better idea to send both to make myself look more well-rounded? I'm applying to UC schools if that matters.

The UC schools ask that you send all test scores, although I believe this policy applies to either test rather than both (you have to send either all your ACT scores or all your SAT scores). Even if this is the case, I think that you should send both scores in the interest of transparency. Your SAT score isn't dramatically lower, so it shouldn't hurt your application. The only reason you might decide not to send the SAT score is if it's a significant financial burden for you to order additional score reports.