You sure can, that's the air injection port, otherwise known as the thermactor bump. You can grind it flush with the rest of the port, that should increase flow substancially. When you're done, can you post pics? i'm going to port my E7TE heads as well and just want to see an example of one that's done. Good luck!
------------------
previous name: 84stangLX
'84 Mustang 5.0 LX
my LX
'89 Mustang GT
my GT