Mate they're Definately bigger that 45mm my motor is far from standard and it's got a huge cam.. Therefore it can handle more fuel (well needs more fuel) I dunno off the top of my head what the model numbers are but I do remember that they are matching numbers.. If you don't wanna believe that they're big that's fine you don't phase me I know that it's true and so does joe at hi-comp performance he re jetted the carby and tuned them..