Is my PSU enough for GTX460 SLI?

looking to increase the graphics power of my system for future FPS's. Already have one 460 so i figure the cheapest way to get graphics power is to throw another one in, unless anyone can think of anything cheaper than $160?
My PSU is a Corsair TX650W, does this seem like enough for reliable gaming? My cpu is a i5-750 with no OC'in. Also, I'd like to be able to OC my cards a bit just to get as much power as possible.