I was tightening up the lower heater hose clamp to the water pump today on the 73 SD Formula and had to remove the 80 amp alternator idler pulley assembly in order to get to it. So I finally got a photo of the EUN (Engine Unit Number - not to be confused with the VIN), on the front of the block that is hidden by the idler bracket. The car was ordered by Enrico Stein on 05/09/1973, shipped on 07/19/1973 and delivered to him on 07/31/1973.
Here you go:
