A lot of people don't believe the "4 grams of Tylenol" thing because it's a relatively moderate amount and a lot of people have exceeded these doses without negative effects, including myself. Well, you don't need side effects to realize something's going on in your body. 7 grams of APAP is almost double the daily dose, I wouldn't repeat that amount again.
I tried to OD using Tylenol when I was way, way younger. I still remember it like it was yesterday. On one occasion I (apparently) ran up to my parents and told them I had just swallowed a bottle of Tylenol, so the amount taken was unknown. I proceeded to throw up for hours, and nobody ever called an ambulance because getting sick was a good sign to them. I have no recollection of this. On a separate incident, that I DO remember, I had swallowed at least 19 generic Tylenol pills, each containing 500mg of APAP. That's a whopping 9,500mg, and all it did to me was make me drop on my floor and pass out for HOURS. I slept for 16 hours, I think.
Hey, I couldn't have been 18 yet at the time, I didn't even know Tylenol can't really kill you at those doses. But in the talk of other drugs, I had gotten these DXM gel caps, each with 325mg APAP. I had 20 (that's what I usually take but this time I had gotten this generic cold & flu shit) and my night was spent with my head in the toilet and out the window.
5 of your Percocet pills aren't going to be detrimental to your health. That's less than half of the daily limit. I wouldn't do that often, though, as it can just wear out your liver. I wouldn't even take over 2,000mg during the day, don't try to hit the limit or you'll just run out of pills and have a horrible stomachache.