We've established previously that I have a 1960 235 block. I was looking at the passenger side oil,passage that runs vertically from directly above the distributor hole up to eventually oil the rocker assembly. My question is: What is the purpose of the tapped and plugged hole in this passage? http://www.1954advance-design.com/Web%20images/1958-60-rocker-oil/1958-rocker-arm-lubrication.html
Figure 18 shows it.
Thanks