The way I was always told by watercoolers before me was 120mm of rad space for each component. So if your running 1 CPU and 2 GPU's then it should be fine. Obviously with 3 components running on the single radiator you will be running a little warmer than 1 or 2, but as long as you aren't running under full load like Folding@Home or crunching it should be fine. And if possible extra rad space is always a plus, as are upgraded fans over what usually comes with stuff like that.

EVGATech_Erik
ToyKing22 if you have some free time you may want to lookup a youtuber that goes by Jayz2cents.  He does tons of watercooling videos so you can get a better idea of how watercooling works and some recommendations.   I'm running a 360 radiator paired with another 240 to dissipate the heat of two GPU's and the CPU.  Average temps under load are around mid 40's to low 50's after a good while.  Running a single radiator would not be my preference.
 
 

i follow him, just never really watch youtube unless i am in the mood to watch something lol... i gotta email back form ekweb people they said it can handle a sli set up, if i was to add another rad it would need another pump... but in my small case that wouldnt work lol,, id need to get a new case too lol