I am currently refurbishing the cylinder head on my 1970 Starfire and have noticed that the oil drain drillings in the bottom of the valve spring pockets appear to be blind.
My initial thought was that this will result in two reservoirs of boiling oil around the valve guides (not doing much for oil consumption) the level of which is maintained by the edge of the pushrod tunnel. Turning the head over and checking the gasket surface I have found two small pilot drillings about 2mm deep which are again blind. Every other head I have worked on (not B25) has these drillings going all the way through the head and barrel.
Has anyone else experienced this anomaly? If so what was the remedy? Or was this another of BSA's bright ideas part way through a model year?
At the moment I am tempted to drill them through but in the back of my mind I am wondering if they are like this for a reason.