[coopdog123]

hey guys, ive always herd that ford 4.6l's are nearly bullitt proof. but how indestructable are they? can you go out and run a stock motor full throttle for 8 hours at a time, or is that going overboard. my friends 4.6 F150 has 230,000 miles on it and it doesnt plan on dying any time soon. i guess my question is, what do you have to do to break one? minus 10+ psi of boost.

[BlueStreak03]

Yeah they're pretty tought motors when maintained halfway proper. I wouldn't go revving past 6K on a regular basis. I think one of the weaker points is the valve springs not performing well in that range. Valve float on an interference engine can cause bad things to happen rather quickly.

[04KenneBellGT]

They are very tough and reliable engines. Another weak point is the bottom end of course which needs to be built for huge power. But im running 10psi on mine and its driven, i dont floor it for hours straight but i have more than my share of fun with it. I don think that kind of abuse would be good for any engine, but it would take a lot of abuse to break something.

[racin366]

They are very solid motors, but like kennebell said, the bottom end is a weak link when you look for serious power. I don't know of many engines that can take 8 hours straight of WOT and not fly apart, I wouldn't recommend trying it, but as far as the average person beating on them, they are pretty damn strong.

[heavy metal]

They are tough.My 02 Gt has 126k miles on it.I have drove the dog out of it.Everything from racing for hours to a full day of drifting,bounced it off the rev limiter way too many times and it keeps on going.

[klrblue04]

well my car has about 110k on it. it was abused by its previous owner(s) and its still strong. we also have a 2002 f150 with the 5.4 and it has OVER 300,000 MILES on it. and that's not a typo. and they were also very hard miles, yet it was properly maintained because we are its only owners, and its still a haus. so IMO Ford is the best when it comes to building quality automobiles