I recently bought a ´72 Sportster basket case as a project. When I asked one of the local gurus about having hardened valve seats installed, he told me that the ´72 was an oddball, and because of that, I´d want to send the heads to a specialist. He said that this year´s heads aren´t swappable with other year 1000s, so if the machinist screwed up, I was SOL.
Is this true? Are the 72 heads that different from later 1000s?