Chances are it has the 403 and the guy purchased new pedals with the intention of changing it over to Manual and then he found out he would have to replace the motor in order to get a 4 speed so he just sold it.
As for the 403 being a junk motor that is not true, they can put out some impressive numbers as long as you do not over rev the motor. as TA6point6 mentioned it is a torquey motor.