So I am getting a new z97 motherboard and a 4790k.
My current system has 1x 360 rad cooling a 780ti and 660ti (physics) and a Corsair h70 cooling my I7 970.
I was thinking about putting the 4790k, 780ti and 660ti all on this same loop. Would probably shoot for an oc of 4.5 or so on the cpu.  
I am certain a 480 rad would perform quite a bit better but was wondering what others thought about my existing configuration.                                                                                                                                                                                                                                            I would like to here some expert opinions on this matter and look forward to any response.
 
 

I have a 360 Rad cooling my 4790K and a R9 290. I currently do not have it OC'd but my temps are pretty good. idles around 28C CPU and 32C GPU load temps are in the low 60's. When I get more time, I will OC, but I am still moving into my new apartment.

I just recently got everything up and running again. So far I have the 4790k overclocked at 4.4 with 1.24 voltage and 780ti clocked at 1172 mhz. I havn`t done much testing yet but with everything on a single 360 loop. My CPU idles at 28 to 31 and loads at 55 to 58. My GPU idles at 29 and loads at 38 to 42. These temps.
were observed before, during and after a 2 hour session of Rome2 Total War. This is a very CPU intensive game and I have my version heavily modded with nearly all settings on extreme. My board is running the CPU at constant 4.4 by default. I am fairly happy with these early results and must say that so far the 4790k has impressed me.
Keep in mind I am coming from an X58 platform and I7 970 CPU so quite a performance boost has been noticed.
Since I had such good luck with my Gigabyte X58 board. I decided to go with a Gigabyte Z97 board.                                                                                         Something of note that may help other users that might have recently purchased a Gigabyte G1 Gaming series Z97: Mine came with the F2 bios which is an early
bios version. Upon initial boot up the board set the correct 4.4 Turbo profile but was pumping 1.45 voltage which made it very unstable. This is a known bug with certain Gigabyte boards and the 4790k in particular. Once I flashed my board to the latest F5 bios, my board immediately set my CPU to 4.4 at 1.24 voltage and my memory to its proper 2400 mhz. This bios is obviously a dramatic improvement over the early bios with vastly improved stability and CPU microcode features.
I highly recommend flashing to a later bios to anyone running a similar setup to mine. Naturally anybody doing so should proceed with caution and visit Gigabytes website to insure that the exact bios is downloaded for their particular motherboard. Gigabytes UEFI bios is a bit weak in comparison to some other vendors. However their QFlash bios utility is a very nice tool. I used it with the downloaded bios update saved to a flashdrive and the whole process took about 5 minutes to flash the new bios. It all takes place in the system bios and completely removes the operating system from the equation. Which in my opinion just eliminates one more potential thing that could possibly go wrong.
All in all a fairly enjoyable experience so far with my new CPU, board and RAM (G-Skill ARES series seems to be very good quality and runs rock solid stable at 2400 MHz)