yeh, i get it to.... chamber + gasket = 30cc (1.0)
and ..................chamber + gasket + dish = 38cc (1.3)
so 288 divided by 38 = 7.6 : 1 ish, a bit low really (laggy ?) 
i still favour opening up the combustion chambers (4 or 5 cc availiable with ease imo)
