Here is a copy of the rebuild manual I am referring to:
http://www.canadianmilitarypattern.com/1960%20235-261%20Engine%20Manual.htm

It states on page 7-16 Note 1 "spark vacuum line disconnected..."

Its not a complete guide, only the section that concerns the overhaul.

Most of the online guides that I have found are 57 or earlier. Since the motor is a 58-59 I was avoiding pre-58 manuals as from what I understand the 58 motor had hydraulic lifters vs mechanical.