Changed my oil the other day and... I only was able to remove 4 quarts.

[07 Boss]

Oil wears out and gets dirty. 7 quarts last longer than 6 quarts.extra margin of safety if you get an oil leak. What kind of bad things. 46 years, over 40 vehicles, and 1.4 million miles driven, says bad things don't happen.

Well a single qt will probably make no difference but overfilling the oil can lead to cavitation with the crank and then loss of oil pressure. What I meant was that I don't think there is much advantage or benefit and having extra oil may cause issues. If the oil is getting dirty or worn out, change it. I change my oil much more often than most because I don't run a PVC system. I get more fuel and junk dissolved in my oil which breaks down the viscosity quicker. I go about every 3K-4K between changes.

 

[Laga]

Although it’s rare, I’ve had two vehicles get oil leaks from road debris and another from a faulty oil pressure sending unit while driving. It only takes seconds to toast a oil starved engine. Like what happened to my friends 04 BULLITT when his son didn’t see the old oil filter gasket stick to the block. Sadly, the kid thought the smoke that was being created was from spilled oil and not leaking oil. The extra oil gives you extra time to react to a problem. I never said to fill up to the point of causing cavitation and an extra quart in a V8 does not cause this. I really don’t know why some of you are getting so upset. There are dozens of examples of things that are “known “ to be facts about cars and engines that just aren’t true. I’m not telling anyone to do this. The OP was worried over nothing and I was trying to tell him it’s ok. There is a little wiggle room built into fluid levels. If there wasn’t, there would be hundreds of thousands of dead cars on the side of the road. BTW, I change my oil every six months. Which is about 1500 miles.