I thought I saw a post on here a while back about fine-tuning a 4 bbl using a vacuum gaue to get both bbls equalized........not 100% sure it was on this site, but I tend to think so........anybody remember seeing that, or can find it again ?????

 

All a vacuum gauge will do for you is tell you how much vacuum your motor is pulling at various rpms, and that is about it. If you are reading low vacuum, then you know that you have to play with timing, or fix a vacuum leak, or something of the like. The only way to truly tune a carb is to get a wideband air/fuel ratio monitor to see if you are rich or lean at a certain RPM. You can also get a good idea if your carb is too rich or too lean by reading spark plugs (clean or sooty) or just tuning until you feel that you are not pig rich, and still making good power.

 

You can use a vacuum gauge to tune a carb. Turn both screws in till they bottom out and then back them out 1.5 turns. Then adjust the screws equally until you have the highest vacuum reading you can get.

 

Are you talking about an edelbrock carb? With the idle mixture screws? You don't even need a vacuum gauge to tune these.

I thought he was speaking in terms of richening or leaning

 

Any carb can be tuned like this by turning the mixture screws. When you have the correct timing and idle speed the vacuum will read its highest when the mixture is good.