Will this bottlneck my pc?
Purchased my CPU 5 years ago, it is a i7 2600k @ 3.40GHZ(not currently OC'd) . I was thinking about upgrading the ram from 8gb to 16gb and my gpu from a 660 ti 2gb to a 1060 6gb. Will this cause any sort of bottleneck? Any input would be much appreciated, Thank you.
Absolutely not. You could put any single GPU in with that i7 and you still wouldn't have a bottleneck. The only i7s that could be a bottleneck are the ones a year before your Sandy Bridge. I have a i5-2500k and have never experienced a bottleneck (BF1 is causing issues but that happens with i7 users too). Jumping up to 16gb RAM is smart and a 1060 will max out all 1080p games.
My system is 4.5yrs old but I have upgraded GPU with games and years...I'm waiting for next year to make a new system. You might want to get the 1060 and wait until next year then upgrade the CPU/mobo/RAM. If that isn't an option...then just get 1060 and more RAM and have fun.
go for new ram & the 1060 the sandys are the best of the gens to me i got an i5 sandy bridge laptop & built a sandy i3 desktop & found they as good for gaming than the next few gens that have come out i found tho extra ram going over is better i will later on build an i7 or maybe xeon for server duties i stock up on the older gen parts atm building another brand new hasswell i3 for under $150 cpu ram & mb all brand new lol but i like building & learning new tricks with the outdated stock intel forgets about they are released.