It all depends on the space between the back of the case, and the HDD bays inside.
Some cases have the HDD bays mounted specially higher or lower to avoid this. Every case has different dimensions and interior layout. The only way to guarantee is a fit is to check the length of the GPU and then check the case specification on the manufacturers website.
If your still unsure, email the manufacturer and say something like:
"Im looking to purchase this case and will be using it with a ATI 6770 graphics card that is XXcm long, will this card fit without needing to modify the case in any way?"
And just see what response you get
Most manufacturers are happy to help since your buying one of their products.