I have close to the same combo with less cam (hydraulic .484 lift). Same gears as yours. With slicks and open headers mid 12's. With 255 60 15" I can just get into the 12.90's. I would think your traction and converter would be the only thing that might hold you back. Mine is in a 62 Sport Fury with a 3500-4000 stall converter, and it is driven on the street most of the time. Also, the converter doesn't give me any trouble on the street, even in the traffic of "Back to the fifties" car show, the best car show in the world (yep, I said the world, and I have traveled all over).

Also, you may want to experiment with more overall timing, up to maybe 38 degrees or so, whatever runs best.