Hey, DD block has used diferent mounting holes for mosfet chips.
EK block used the cutout lids in the PCB to mout the block for mosfet contact, so did Aquacomputer, and as 580 card does not have those lids blocks are not recomended to mount as mosfet chips vill most likely not have proper contact and the care will be bent. Therefore EK does not recomend to use 480 block with 580 GTX card.