Thanks for clarifying, Kestas.
It confirms what Amsoil's 4-ball wear chart says. Around 2002, most likely when the CI-4 version came out, Delvac 1's wear scars became pretty bad, > 0.60 mm. Older data from 2000 show a scar diameter in the low 0.40 mm range, slightly above that of Amsoil's own products. This was likely from the CH-4 version.
Again, we all know that 4-ball testing does not tell us a whole lot about an engine oil. The 4-ball wear test is just one among other test indicating "nothing". From Amsoil's mc oil comparison, I remember a good 4-ball performer showing bad results in the FZG test, while another lube with a large wear scar reached a high stage in the FZG test.
Whether these tests are relevant or not, I love to review them!