Factory overclocked ones are yes. I was using stock 670 performance as a basis for comparison because we know stock 760 performance is slightly higher (by design) and so we know stock 760 SLI would be slightly closer to GTX690 than stock 670 SLI is, and from that guesstimate that a pair of 760's in a Mars running insane clocks could get well within striking distance of GTX690 in "out of box" performance.
No, stock vs stock, the 670 is better than the 760. By design, the 670 base info shows more processors/shaders, just a slightly lower core clock.
http://www.bit-tech.net/hardware/2013/06/25/nvidia-geforce-gtx-760-2gb-review/4
http://www.bit-tech.net/hardware/2013/06/25/nvidia-geforce-gtx-760-2gb-review/1
http://www.anandtech.com/show/7103/nvidia-geforce-gtx-760-review/10
And yes, it would have to be insane clocks but there is a limit to how high the GPU frequencies can go stable.