Here's the full article from the GSCA newsletter. It appeared in the 80's or 90's. Considering the source, Dennis Manner, it's as accurate as can be!
One thing to be aware of is that Buick measured the duration at only 0.002" lifter rise.....while most cam manufactures used 0.006" for the advertised specs. End result is the Buick duration numbers are inflated, making it difficult to use for comparisons.
A more common spec for measuring duration is at 0.050". I carefully measured a stock 66 GS 401 cam (used) and came up with:
309*/298* Intake/Exhaust duration at 0.002"
271.5*/266* at 0.006"
209*/208* at 0.050"
Lift was 0.448" Intake, 0.425" Exhaust.
Rocker ratio is 1.6
Doc raved about the '090' cam (last #s in the pn) in his cars. The closer lobe separation, 109* vs 114*, is desired for performance. It's rumored Buick went to the 114* to improve idle quality due to customer complaints about the lumpy idle!
Buick also used the hotter 090 cam in the 66 GS 401 with the Q-jet option