Just sett the mixtures on my carbs after striping them down. 2 3/4 for 3 of them and 5 1/4 for the left rear one . Rechecked it 3 times . Using card tune.am i missing something ?. Didnt think there should be that mutch differance.
Mixture screw adjustments while monitoring vacuum gauges is not something typically done. The synchronization process is mechanically setting the linkage so all four butterflies open identically...or at close enough to allow vacuum to develop at low RPMs equally across all cylinders. (Synchronization)
Generally, the mixture screws are a fine-tuning, usually last step in the process. And they do just as their name suggests, adjust the idle mixture. Most folks do that by ear using the idle drop method.