[jhv48]

As KC stated back on February First.
The chain broke, valves hit pistons. Not an assembly failure, a parts failure. Send the engine back and he will fix it. The fact that you don't want to and choose to air your concerns on this forum is, once again, your choice. As far as I see, there was no problem with the heads, only the timing chain. They may have been reworked too much, but they didn't fail. The chain did, and when valves start hitting pistons, cracks can appear everywhere. Whether they were there before or after the incident is pure speculation. Needless to say, they won't be going back on the engine. The bottom end is probably fine but needs inspection to be safe. So, once again, end all this and simply sent the box of parts back and let him honor his warranty.

If I built that engine, then I personally would want to inspect it and the damage after the failure. I wouldn't take anyone's word unless they were my authorized agent. If you want it fixed, send it back and let him do it.

You may not want to have KC do the rebuild, and that is your choice. But then don't expect him to just send you a bunch of parts either. That's not how warranties work.