These are the carbs originally fitted to works Cooper S models and have to be fitted by some classic/historic racing classes.

 I fitted these originally to my works replica of the Mk2  works mini ORX cars. They utilise a pair of refurbished H4 carbs fitted to an S manifold with servo take off. They ran only very briefly to drive the 1293cc  car to Southern Metro for split webers to be fitted as the ORX cars. However they are correctly fitted with needles and dashpot springs to suit the larger bored minis and ran very well.