Onebad95 has an AODE 302 convertible. He dyno'd 283rwhp and ran 12.9 at 105mph on his one and only pass at the drag strip. Its not a 331, but it's an example of a NA auto vert.
I would guess with decent heads, and a cam, an N/A 331 aode with a convertor would put down about 320RWHP or so. With traction that should bring you in the mid-low 12's.