I have seen drawings and photos of the vacuum line running around the front of the valve cover along with the vacuum advance and fuel lines. That way the VC can come off for valve adjustment without disturbing the lines.
1951 3800 1-ton "Earning its keep from the get-go" In the DITY Gallery 1962 261 (w/cam, Fenton headers, 2 carbs, MSD ign.), SM420 & Brown-Lipe 6231A 3spd aux. trans, stock axles & brakes. Owned since 1971.