More Info!
 

Spoke to the Machine shop1 He claims that no valves were bent. He claims that the two valves that were bad comes from two cylinders running lean.

Either Injector problem, wiring problem or something else causing the cylinder to run lean and develop the problem
He claims that the condition would take 15000 miles to manifest itself.

Again, how can we get such good performance prior to chain replacement, get a valve noise after chain installation and have these type of problems discovered?

The caps I referred to in the above post are called lash caps and as stated two of these were thinner than all of the rest!

I'm still confused!

Can anyone give me a thought here?