yes, you can overclock the turbo slightly. depends on your motherboard though.
I doubt overclocking the turbo will really matter in the end. That cpu is already fast enough at stock speeds to pretty much do whatever you want with it. It will already play almost any game (there are SOME games that are so poorly coded that you'll need to overclock the turbo, but those are few and far between)
And no... that cpu won't bottleneck a 760... frankly a 4 year old dual core phenomII wouldn't bottleneck a 760 significantly.