Step 1 : Introduction to the question "What was the #8 hit of 1968? This song was an instrumental, so I can't give you lyrics to help you guess. I can tell you that it bore the same name as the spaghetti western, by Sergio Leone and starring Clint Eastwood, that it was the theme song for."
..."The Good the Bad and the Ugly" was written by Ennio Morricone and performed by Hugo Montenegro. The excellent whistling was performed by Muzzy Marcellinno. (Yes, it was a person, not a synthesizer!)