Largest Aftermarket Video Card that will fit Dell 3000 Desktop I3847-10000BK

Hello, I purchased this dell from staples and was wondering what was the largest aftermarket video card that will physically fit? Came across this thread that has basically the same case set up but when I measured up to the power cable on the mother board (plug that's circled in second post) I'm around 9.4/9.5 inches while that picture is closer to 7 inches. 

I'm looking to put in a r9 380 or 380x which some are 9.3/9.2 inches long and seems like it could be too tight.

(I know psu needs to be upgraded)