Slant 6 225 valve adjustment

You have a more important question to ask: Was a no-retorque necessary head gasket used?

If it was (and he knows that for certain) then I would suggest re-torqueing the gasket anyway (and then you'll need to check the valves, of course).

Why? I ran a cognitive science experiment that involved memory. I cannot get into specifics because of subject privacy. Let me assure you, however, that people can have very distorted memories -- even highly intelligent subjects who were immediately bragging to the principal investigator (moi) about how good their memory was and who then glanced at their data -- yow -- and nodded politely with a smile. One of the effects being studied was negation.

Negation means that it is very possible that the person will recall the exact opposite of what is the case. It is in very close association in the mind.

Sure, it is possible that ONLY no-retorque gaskets were used in the shop. I might believe the mechanic if he had a set of build notes that he kept and I knew that he had established a set pattern for recording information about the parts used BEFORE they were installed. A receipt with a traceable part number would work as well. My brother is an aircraft mechanic -- I need to remember to ask him how they document their work.