aah, Thanks. Any idea why they function differently? Does one have a mechanical advance return (spring) and one returns by vacuum alone? Also the timing on these cars should be set with both lines plugged in or un plugged? The base timing is listed as 2 degrees BTDC @ 650RPM on the radiator support tag, however it was added by the US importer on the 83, so I am not sure if it's correct. What is the optimum setting?