So I have 2 of these, they appear to be slightly different. One uses a different type of vacuum advance set up. the 80 has a physically larger advance unit that has 2 vacuum ports on it one on the front one on the back. the 83 unit has a physically smaller advance unit with 1 vac port. Both are from euro models with the M110 engine. Is one better than the other to use? Are they the same or different advance rates / amounts? As far as I know these were both from the 185 HP motors.