well let me ask this because it seems a lot o cards are packing more memory if I where to do 1440p gaming and the 2gb vram turns out to be not enough would it be enough if I put 2cards in a SLI config thus making the combined vram 4gb between 2cards
There are some rules of sli and crossfire. If you sli your gpu, then you'll be having two of them for sure. Let's say they both are clocked at 1000 Mhz, that doesn't mean you have 2000 mhz gpu in that box. Same rule follows here, even if you sli it with another 2gb 770, it's vram will not get doubled, it will remain the same (2gb).
Definitely adding one more gtx 770 will give you almost 98% of fps boost on 1080p and a bit less boost on 1440p and 4k.
But surely 2 gtx 770 for 4k gaming will be enough.
If you really wan't to upgrade then sell your current gpu and get a r9 290 or 290x 4gb and then crossfire it later making your rig ideal for 4k.