Did I get the wrong size case?

[Diesel_Power]

Hey guys, I made a thread earlier about buying components for a new computer.
http://www.hardforum.com/showthread.php?t=1367967

Well I got most of the pieces today (some were on back order) and when I took the case out of it's box (Antec 900) I thought to myself it looked smaller than I was expecting. I then took out the heat sink (Xigmatek H.D.T. S1283) and just by eyeballing it, it looks like it'll just barely fit.

I'm also thinking the same thing with my mother board (ASUS P5Q PRO).

Am I looking at having to return the case and get bigger one? Or will I be alright? Will a heat sink and mother board that just barely fits in my case present a problem?

 

[Dangman]

You'll be all right. You might see slighlty higher temps since everything is cramped but nothing to worry about.