Your case should accommodate, no problem... The layout of your motherboard (spacing of the PCI-e) slots is key, as you do not want to choke the top GPU's fan air-flow though, in doing your SLI if you can help it.
If not, you can expect exceedingly high temps with your SLI setup, even if the bottom card is disabled and GPU fan requirements to be set to manual/high. This is in turn will equate to higher noise levels.
Another thing to consider with 3-slot GPU's in SLI is, don't expect having room for other PCI-e slot components; this is dependent on motherboard layout.
If this is an issue, a 2-slot card setup would be a better route OR even a water cooled 980 Ti SLI setup, as the cards are typically smaller, run WAY more cooler...