Vortec 7.4 no oil to rockers

The 2 year time span is only the time from when it started to when I could finally get it to a repair attempt.It was driven very little with the lifters tickiing and the low oil flow to the rockers was only noticed after reassembly last month and the subsequent 300 mile trip. It sounded fine and the assembly lube must have lasted for that 300 miles before finally giving in. The drivers side rocker cover is removed and i do get oil flow to the center rockers. It's enough for one of them to squirt it across to the inner fender. I had to buy MR. Gasket clips to keep it under control. Like I said, the oil from 2 rockers still fills the head and spills over onto the exhaust manifold. I'm going to have to find a spare cover and cut the top out of it because i cant run it for very long for fear of starting a fire.

There is one possibility that dooms the engine, and that is spun cam bearings. This is barring some problem with the replacement lifters. If i get oil to some rockers sometimes then it could be that when a cam bearing spins in the bore and lines up the oil hole all owing oil to pass. Yesterday I ran the engine and got no oil to the rockers after sitting for a week. Totally dry and I now noticed a tick.So if it is cam bearings the oil holes are not lined up shutting the oil flow off like a valve.