With all the emphasis on oiling, here's where I am now. It occurred to me that if I had partially blocked oil vent holes on the #4-6 valves that the crud came from somewhere. So I pulled apart the rear half of the rocker assembly and ran the used rocker arm shaft through the parts washer. I cleaned out some old oil sludge. I put it all back together and it's still oiling the rockers unevenly. #4 exhaust isn't dry but it doesn't weep oil from the vent hole. #6 intake spouts like a geyser. I changed the oil and filter so now I'm running 10W30 detergent instead of 30W non-detergent. None of the valves are bone dry and they all have some sort of inner seal/shield under the metal cap inside the spring (umbrella?) that only reveals about 1/4" of valve stem above the valve guide to splash oiling off the spring. I squirted all the valve stems with a shot of 20W50 oil from an oil can for good measure. All the springs are installed correct side up. So with all this tinkering, oil changing, and sludge cleaning, what else could I do but go for a test ride? It ran great cold, but at the appointed time and distance, same old @#%*! Seizing valves. Intake and exhaust both from the sound of it. I limped home and pulled the valve cover and used a length of garden hose as a stethoscope to try to isolate the noise. #4 exhaust (the one with no oil from the rocker weep hole) sounded noisier than the rest.

Does this starving/geyser scenario on the rear #4-6 rocker assembly sound bogus to you guys too? It's all clean now and I can't figure what's up. I could reverse the new front and used rear rocker arm shafts and see if the problem migrates to the front #1-3 assembly. I could start up two other trucks with 235's in them and see if they oil the same way. Or I could quit screwing around and HOPING that the problem goes away the easy way.

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