Is this good enough for engineering schools such as stanford, cal tech, georgia tech, MIT, RPI, Cornell...?

you have a good chane at any of them. However, almost all of them are very unpredictable as to who gets in as they have acceptance rates under 20-30%. You should be fine at Georgia Tech, RPI, WPI, Stony Brook, Purdue, Penn State, and Michigan State. You have a good chance at the others, it is just that everyone applying there has good grades and scores as you do. Hope this helps.