Thanks for the help decided to do with 2x 120 in the bottom, moved the old 140mm from the back to the top, and added a new 140 to the back.
Thanks for the tips.
I'm not sure if this is the right spot to post this and i'm sorry of i'm wrong.
I bought 1x af 140 and 2x af 120.
The 140 went in fine, both the 120's however have there screws half in and now seem to be stuck.
Anyone with Any tip in how to solve this?