Z77 Upgrade for SLI use with aftermarket coolers and PCI sound card

I don't think you should have any problem.
For example, here is one:
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

But...
What do you want to achieve with a $70 aftermarket cooler for the GTX670?

If you think you can OC it more, then why not just spend that $70 more on a GTX680 in the first place? I know, I know, the GTX680 is hard to find. But that situation will change.

For less than a $70 delta, you can buy a superclocked version of the GTX670.
Graphics card vendors are binning their chips, so there is no guarantee that a stock card will have great OC potential.

Or, for about the same $, just get a GTX690. Crazy.

Actually, the coolers on the stock GTX670 should be adequate. The cards run relatively cool because of the 28nm manufacturing process.

In the end, just how much better than stock GTX670 sli do you really need?

I'm not sure that mobo will work, I think the aftermarket coolers need 2 slots of clearance, not just one (but I'm not 100% sure on that).

The reason for the aftermarket coolers is noise (and temps as an afterthought). I got a Gigabyte OC GTX 670 2GB last night, and in furmark after 1 minute, the fans were LOUD and temps were around 90C.... This is at stock speeds and fan set to auto.

This is in a silverstone ft02, so one of the better ventilated cases.

The reason I went with the GTX 670 route is it seems like the best bang for the buck with a slight overclock. I will only get one for the moment, and as games need more horsepower, I'll add another down the line.

What is your budget? I purchased a Gigabyte Z77-UD5H for around $150 from MC. It's great. All great reviews, and will be easy to add another GTX 670 (I have the same card).

My budget isn't really an issue. I was just wondering if any Z77 mobos out there have enough clearance to use SLI with aftermarket coolers (so 3 slots per card) and still have an available PCI slot.

Are you using an IB processor? I've heard some bad things about that mobo when used with IB.

Yes, I am using a 3570K. No issues to date, but I haven't overclocked it yet. I wasn't aware of any issues when using IB specifically to that motherboard. I know there are general heat issues when overclocking beyond 4.5 ghz iwth IB. I am not sure about 3 slots per card. I'll look when I get home. It does have proper spacing though for SLIing two slot card