It is tough finding a general boat surveyor that can do a full engine survey. Many won't even take engine oil and gear oil samples. Just be sure to ask the questions and know what they will do before you give anyone the go.
Most general boat surveyors will only shoot temps of the coolant loop, seawater cooling loop and dry exhaust elbow. Try to find someone who will at least crawl around , use mirrors to view obstructed areas (oil pan) and have a mechanical surveyor in their back pocket for follow-up if they discover something. That's what Bob does and I'm sure Ken's brother does too. Better yet, have a general and separate mechanical survey with someone like Mack Boring or another reputable outfit .. possibly a certified dealer. Nothing is ever 100% as there is not an owner out there that will let you start tearing components off of the engine. If you start and they're around, they'll look like this
and then this ..
.
All the best.