GTX 660 SLI design question

This is my first post to this board although I have kept up with the YouTube side of Tek Syndicate for awhile now. That aside, I have a specific question about the EVGA GTX 660 in SLI. The one I have right now is the blower type design and it works very well for me and stays nice and quiet. But I worry that if I run them in SLI that the top card will not have a large enough access to cool air; so maybe I should get the 660 with the ACX cooler on it since it seems it can grab more fresh air than the blower type. If any of you have any suggestions please let me know. This isn't a matter of time since this probably won't happen for awhile anyways. Thank you in advance. 

How much space are we talking about, each card takes up 2 PCI slots in space, is there 1 space in between or none on the motherboard you're looking at?

The board is a ga-990fxa-ud5 and from what I've seen the cards are right on top of each other with little clearance. 

hmm a blower might not be a bad idea if you compare the two, i have an ACX cooler on my 780 and it ejects almost no heat out back of the case...most of it stays in the case. The blower on the other hand exhaust a lot of it's air out back of the case, but makes more noise and look aweful :D

So if you have good airflow in your case, you can go with the acx solution and considering what kind of case you have i'd guess you have enough airflow :P.