I know. What I mean is don't dilly dally while changing your oil. As soon as the oil draining out turns from a constant stream to drips, plug it back up and refill it. The longer you take the more oil drains from the skirts. The ford V10 had a similar problem and people found that using a thinner synthetic oil and prefilling the oil filter helped get oil to the pistons faster reducing the marbling.
Mine makes a noise similar, goes away after the engine warms up. It's not the valve train.
The person I bought the truck from replaced the engine with a long block assembly from AutoZone.
2000 XLT, 4.0L