I have a Dell 2407WFP and a HP 2335 that I run in portrait.

> So after doing some research I think it may be my monitors dont support it.

If you're sure about this then *don't* do the following. Sometimes the monitor does support a particular mode but the driver info is not accuracte. You can force the monitor into a particular mode by unchecking "Hide modes that this monitor cannot display" in Display Settings | Advanced Settings | Monitor. Be sure to note the warning about damaged hardware.