Can this power supply manage SLI?

Nice build that, not much I disagree with! I'd get 16GB ram but it is expensive atm so maybe 8GB will do for now. That PSU will be totally fine with 2x970s & that CPU etc. Anyone who tells you otherwise is wrong.
My current build is a 2500k@5GHz on 1.40V with 2x680s, all custom water so that includes two pumps & 3 HDDs as well as 2 SSDs. That's all running fine on a decent 750W PSU. I'm right near the limit mind you (~730W drawn from the wall under extreme load, i.e. prime95 & Furmark) but your system will be far less!
I just want to note here that a *decent* PSU is rated to SUPPLY 750W, NOT draw 750W from the wall. At ~85% efficient that means I can draw over 850W from the wall before it begins to be a problem. That plus any good PSU can handle going over it's max rating for short time spans, i.e. seconds to minutes not hour-long gaming sessions!