The horse is dead

Newbomb...You probably know double what I do about assembling engines. My reference to “clueless” was about how you stubbornly stick to the belief that everyone should expect to modify things to get new parts to fit.
They would expect it IF they are warned of it OR have dealt with the vendor before.
File fit rings are obviously filed to fit the bore.
A simple “pushrod clearancing may be required” would have made all the difference.
I am equally ready to bash a customer that bad mouths a business when they expect too much. There are idiots that think all vendors are out to rip them off and when they make a poor choice that doesn’t go their way, they want to blame the vendor OUT IN THE OPEN instead of calling the vendor to straighten it out.
Honestly, at first I did think that this was one of those examples.
Have you ever dealt with a doctor or an engineer? Sometimes they get really rude if you question them. That arrogance is something that I refuse to tolerate.