[aaronblevins]

Yeah I'm positive they set the timing. I'm not saying don't use a vacuum gauge for timing. I'm saying most of the time you advance or retard the timing when you have a light on it. Also reading vacuum I guess. When I set the mixture screws the other day. I did it just as holley suggests. With a vacuum gauge. Reading the highest amount of vacuum while making equal turns to get the highest amount until you pretty much make no more positive change. Set the screws all the way in... backed them out a turn and a half and went to work.