I read the modifications done to the 1976 Vanguard from the link the Craigslist thread. The author mentioned that change and it was the first that I heard of it. He also modified the boat for carbon masts, that makes more sense now. Just lots of curiosity on my part.When that boat was built you weren’t permitted to have a range of adjustment. But the pivot bolt location and range are the Sam e, so I suspect it’s fine. The tolerance was millimeters, not centimeters. So a range of 3/8”. New rigs with stiffer masts probably have a placement different than the Needlespar set up.