From what I've read catastrophic timing chain failure rarely happens on the 4.6L. The plastic in the cassette guides wear but the metal reinforced guides don't break. When the chains begin to contact metal surfaces metal particles end up in the oil. The particles go thru the oil pump but should get trapped by the filter to avoid bearing damage. Eventually, the chains will fail from wear. Fortunately, replacing the cassettes only requires removing the front cover instead of removing the engine. Here's a photo of an Aviator DOHC V8 I purchased to install in my next project vehicle (2002 Explorer) if I can ever find one at a reasonable price that is RWD with the SOHC V8.
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If your engine chains are making noise I suggest you repair what's needed without waiting a long time. If your hydraulic tensioners need to be replaced try to find the metal ones. Ford "cheaped out" at some point and started using composite tensioners which are prone to failure. That could be your only problem. I suspect all of the DOHC V8s have the metal tensioners (mine does) but your SOHC V8 may have the composite ones.