Originally Posted by Dragsix
Pre 59 blocks used the steel line behind the side cover. I have not played much with 54 and earlier blocks so hopefully someone will chime in here but I am pretty sure some of the earlier blocks used that line also. I just don’t know how far back.
Wow Mike, excellent description !
If you are referring to the earlier copper "oil line" that feeds the rocker arms it is described in 1935-1936 as passing through the water jacket to quickly modify the rocker oil temp. http://chevy.oldcarmanualproject.com/bulletins/35csn099.htm
By 1936 that line was beginning to be called "valve rocker oil pipe" http://chevy.oldcarmanualproject.com/bulletins/36csn53.htm