I was told they don't exist. I looked far and wide and never found a 2-groove 4-bolt pulley.
I took one of the common 3-groove pulleys, visited a brake lathe and soon had a 2-groove 4-bolt pulley. This was the clean way to do it after running for a year or so on a sawed down 3 to 2 groove emergency driveway conversion pulley, and spending that year or so searching for the non-existing 2-groove pulley.