You need to make sure your pump has the delivery head to push the water that high. If I wanted to buy an inexpensive pump I would put the radiator in the front of the case below the HD rails. The other problem with this type of setup is the difficulty of bleeding the lines as the radiator is the highest point in the system it makes using a res/airtrap really difficult. I'm not saying that setup is bad just difficult and possibly problematic.
Go to
www.dangerden.com and check their pumps out!