My trip to the track...
Ok, we have a good starting place. I think your 1/8 mile times is off as well. Your gears and stall are giving you the 60' time, but you are not pulling like you should from then on. I think your combination should be 12.70's at approx. 105 mph. For example, I ran 12.9's at almost 105 with a 360 with 340 heads and a street mp cam, 3000 stall and 3.91's in 100 % street form. I would put a 750 double pumper on it. I would be running your total advance timing between 37-40 degrees. You could try a new HP mechanical fuel pump, they make them that pump a lot of gph. I almost get the feeling your vacuum secondary's are not coming all the way open.....?????