I just walked into my local car spares place and bought it over the counter. After talking to Mike Feeney he tells me the 240 is different from the others. I usually ask for 280zx parts when looking for engine bits as they tend to list these. The belt I just bought is 13mm x 845mm. I believe the width may be different so I'm not sure what you are supposed to do if the use the later alternator like me.