Should I submit my ACT, SAT, or both?

I am planning on applying to schools for engineering but I am not sure which to send.

ACT
English: 28
Math: 30
Reading: 29
Science: 29
Writing: 8

SAT
Reading: 610
Math: 650
Writing: 670

http://www.act.org/solutions/college-career-readiness/compare-act-sat/