When I got a 48 pickup with a 55.2 235 in it, the rocker feed line from the rear cam bearing was plugged with sludge. There was an oil line Teed off the oil filter supply and run over top of the head to the pipe fitting in the middle of the head. Apparently, whoever did this didn't do it soon enough as the rockers and shafts were shot and noisy but they got lots of oil.
When assembling my 62 261 block with the 848 head of unknown year, I used the oil line under the side cover AND the drilled bolt. The block had the plugs in it. The oil line was was probably unnecessary but I found the instructions after assembly. So I have non-offset rockers and they don't get as much oil as with the earlier 235 block and the same head. But they get enough oil. Previously, the top end was more or less flooded with oil but that didn't seem to cause any oil consumption. Probably tended to heat up the oil though.
