Back in 1978 or so I sold a guy a used hydraulic cam and lifters. He asked me to put it in for him. It was a little hotter than stock and his 64 GTO ran pretty well with it. When he dropped it off he was bragging about shifting at 8,000 rpm all the time.
I noticed his aftermarket tach was set to 6 cylinders. I never told him because I figured if I reset it he would just blow up his engine.
I've posted it before, but if you light off a gas tank containing fuel residue, it will blow up. Yes, beer was involved.
If you remove the last bolt on a flywheel, don't be laying underneath it unless you want the impression of ring gear teeth on your forehead. (wasn't me)
When I was training at a repair shop the top mechanic was showing off how fast he could change spark plugs using an air ratchet. You can guess what happened. Then he decided to start the engine. That Ford made evil sounds as it tried to spit out the pieces of porceain.
Dumb quality control: A Ford service manager was on the phone with the factory about an unusual car that just got delivered. Everything under the hood was for an A/C car, but the dash was for a non-A/C car.
I used to get "Grand Ams came with a 350, right?" all the time.