I did some research and I found out that my 5870 is a non reference design pcb. All of these cards have the fan in the middle. The reference design pcb 5870s have the fan at the end of the heatsink.
Its impossible to fit a non referenece pcb with a reference heatsink.
I opted to buy a new 6970, I will be putting my 5870 in my HTPC and selling the GTX260 thats currently in it now. The PSU in my HTPC is powerful enough for the 5870. This also gives my HTPC HDMI so thats good. I hope I can get at least $100 on ebay for my old gtx260.
Thanks for the responses!