68 340 with factory air lower crank pulley #

The pulley that I am looking for has three grooves. I am being told that the 68 340 with factory air lower pulley is a one of a kind pulley. One of the members sent me a picture of the pulley that I need but because of the computer wiz that I am I can no longer find it. It has three grooves and the front groove almost looks like it was added on and it is bigger than the two back ones. If this does not make any sense it's the only way I can explain it. This is why I am trying to get another picture of it or even a part number for it.
Bob