An interesting paragraph in the excellent book in the picture about tuning SU carbs for the track.
It suggests to have a tuned piston/ needle / damper assembly with a slimmed down needle, weakened spring and no oil in the damper which will have a very close performance to a Weber (but very heavy on fuel).
Drive to the circuit on your standard road tuned assembly then swop on arrival. I may try this as I would like to have a track day perhaps next year.
I am also in the process of getting a set of HIF4 AUD616 carbs ready to install. These have the distributor vacuum port for better tickover and power take up. Also I will be replacing throttle discs with the bypass valve with a plain throttle disc which gives better air flow – the book reckons this gives about 10% better air flow through the carb.
An excellent book well worth a read.