I have a vague recollection of someone holding a track record (at Cradley?) for the wrong way round. I think the only modification to the bike was to remove the footrest.
Of course some of us race "the wrong way round". And before anyone starts making cracks about my two wheel abilities, I am referring to right hand sidecar racing on grass which of course, does run in a clockwise direction.
Actually, since it is your right leg which provides a lot more control of the bike than your left, it does make sense to go anticlockwise.