Here's a trick we used to use back when there were lots of 235's on the road, and oil starvation at the rockers was pretty common. Take the head bolt out where the oil passage comes up, the middle bolt on the passenger's side, and find or make a wooden dowel rod that's a snug fit in the hole. I modified a piece of broomstick. Fill the hole with clean motor oil, put the dowel in, and smack it with a BFH. The hydraulic pressure will clear out any crud in the oil passageway, unless it's really baked hard. I believe that head bolt has a hole drilled in it, or a grooved thread, also.
Jerry
