Mechanic vs Doctor

[4.3LXJ]

A mechanic was removing a cylinder head from the engine of a Chevy V8
when he spotted a well-known heart surgeon in his shop..
The mechanic shouted across the garage, "Hey, Doc, can I ask you a question?"
The surgeon a bit surprised, walked over to the mechanic working on the car.
The mechanic straightened up, wiped his hands on a rag and asked,
"So Doc, look at this engine. I open its heart, take the valves out, fix 'em, put 'em back in,
and when I finish, it works just like new. So how come I get such a small salary
and you get the really big bucks, when you and I are doing basically the same work?"
The surgeon paused, smiled and leaned over, and whispered to the mechanic...
"Try doing it with the engine running."

[XJ Wheeler]

Haha, that's great.

[BlueXJ]

Most heart surgery is done while the patient is on a bypass machine and the heart is stopped. So the joke is invalid.