Unported head quickness?

1972 duster 340, jerico trans, 5.57 gears, 9zx 30 slicks, stock unported heads, 1.88 & 1.60 valves, stock intake & T.Q. carb, 11.37 @ 115.50 mph, 1.49 60 ft, 3335 wgt

Good Lord that is some zippy times for a set up of stock heads, intake and a TQ. What about the lower end? Is the Jerico a 5spd?