All the 292's I have worked on were in 1967 Chevy school buses. They had single groove pulley on water pump and alternator. But the alternator pulley was built so that it was 1/2 out further than the regular alternator pulleys were. Made line up perfect with no spacers and no moving the alternator.

I think I kept one of those pulleys because they were/are hard to get.

Most parts stores didn't know to change them and so many times the customer came back to get the right pulley. Sometimes the alternator had already gone back to the rebuilders and the pulley was with it.