The engineering departments at SLO and Davis are crammed full of people with higher test scores and GPAs than yours. Yes, you’d be on the higher end but you WANT THAT as it gives you the best shot at research opportunities and internships…both of which can be hard to come by at Cal.
Shoot as high as you can but recognize the reality of how the system works. Try to move away from the prestige mindset and start looking at program strength. You might be surprised to find where that takes you for mech eng.
And what @ucbalumnus said. My son’s UC GPA of 4.2 and 34 ACT got him waitlisted at Davis as a math major. Engineering is more competitive.
If I remember correctly, Cal Poly also uses 9th grade grades. MechE at Cal Poly is definitely not a safety with an acceptance rate in the mid-teens or lower (based on 2014 stats).
Are you a girl? I can’t tell by the info you gave; if so, your chances skyrocket. Engineering programs LOVE girl applicants due to the M/F disproportion. I think I saw that MIT’s girl admission rate was 15% or something (I’m not completely sure about this, but I’m pretty sure I saw it).
You may want to shoot higher, just make sure that you are willing to attend all schools on your list including UCD and SLO if they remain on your list and have some solid safety schools as backups. You do not want to end up with no acceptances next spring or your hard work will have been for naught. It is very hard to chance just using Stats since essays and EC’s since they are all part of the package. As many posters have stated, there are no guarantees when it comes to the UC’s especially UCB. Apply broadly and Good Luck.
Look into the ME program at SLO. It is very impressive and would not be a waste. Small classes and hands on “Learn by Doing” might be just what you are looking for. On top of that the tuition is less than the UCs. If you are worried about a $70 application fee, you need to look at tuition as well.