I love SUs. So easy to work on, to adjust etc. etc. Mind you, you need to know a little about how they work. With multiple set-ups, a "floating" vacuum gauge is a "must have" tool in order to make sure that each carby pulls its equal weight. Adjusting the mixture is reasonably straight forward, and is usually achieved by lifting the "checking" pin. However, it can take a bit of time to get that right - the most accurate assessment is to run the engine, or drive the car, for at least ten minutes on a steady throttle, stop the car and remove four plugs (on a V8) and compare the colours of the plugs. A nice grey colour is what you need to look for. Regards Styria