My rockers weren't getting much oil, mainly 123456, even though my oil pressure was reading healthy. I stripped it down, expecting gunge/blockage in shaft/rocker holes. It was pretty clean, though the shaft had worn heavily at front of engine, going less so to rear. This meant the small scroll oil channels that are inline with the exit oil holes in shaft, in the rocker areas were non existent.
New shaft and oil was coming out of the rockers.
I should check it, as now 2 years down the line, as the new shafts have a poor reputation. I think some folk view it as a replacement service item.
On second thoughts, the rockers weren't noisy and no quieter with new shaft. Maybe I could have reground the scrolls on old shaft with a dremel small disk and got the same result?.
Dave