Looks like Chevy didn't use the bypass-pin starting with the 61 cast any longer...
[img]http://www.siegmundguitars.com/images/engine/close-up[/img]
I checked my 60 truck shop manual and a chapter (8-6) and picture does show the pin and also the original filter position.
It suggests using a jumper line if the filter and lines are removed and never to plug the out and inlets, but doesn't explain the pin and it's purpose anywhere I could find.
Seems a little odd with the otherwise very detailed manuals of that time.
