The owner's manual supplied by Ford with every F-150 lists the various specifications for the engine, including fluid capacities, Motorcraft brand replacement part numbers, fuel octane requirements and basic engine data. Anything heavier can result in severe complications. If you look inside the wheel wells behind the fender liner, right about where the frame is one O2 sensor, the other is underneath the truck about half way back in relation to the transmission. It keeps your engine running smoothly, and without it you would have catastrophic engine failure before long. I also have a F150 5. Maybe on a dyno, under all kinds of controlled conditions, but not in real life. I also seriously doubt that a 1957 Chevy was on that Vehicle Application List of vehicles to be serviced with 5W-20 oil.
. You said they changed the oil because the tolerances are tighter. Even my old 87 Mercury was only going through a quart every 600 miles and that was with 420k miles on the clock. My comparison was a 1957 Chevy to a 2005 Ford. All vehicles are subject to prior sale.
This also voids your warranty in most cases, leaving you to pay for repairs for a brand new vehicle out of your own pocket. The engine has been designed to operate on gasoline with a minimum octane rating of 87. Some types of oil are thicker than others; if your engine has smaller holes and valves for the oil to pass through, thicker types of oil can be inefficiently pumped throughout your engine, which ends up causing metal-on-metal contact and leading to terrible engine failure. Since the switch I have seen a big jump in rear diff bearing failures on those trucks. Note, most of the driving is city commuting and occasional local trailer pulling. I never had bearing issues, and I admit it was a bit of a struggle for this old-fashioned guy to stop using 20W-50 racing oil and go to 0W. The 5W20 may have something to do with it.
That may be true for Ford, but engine tolerances for the luxury brand, and the Japanese brands, have gotten much tighter over the years. Using a higher viscosity oil can do damage to the engine, in the amount of time that it takes the oil to heat up and thin down. I seriously doubt the tolerances are much tighter at all. In fact after doing a little research i found that they have not been carburated since around 1990. My dad suggested using 15W-40 which seems a little excessive to me. Which also contributed a bit to my paranoia.
Stops and starts consume more oil than straight driving or driving with Towing on distances. Makes changing it a breeze. Now I know if the manufacturer says to use it it should be ok but to be honest the idea of using 5-20 makes me uncomfortable. Modern engines are machined to a lot tighter tolerances than your dad's 1957 Chevy was. The 0W stuff was literally like water, but very slippery! The reason that today's engines last longer is that all the parts fit much better. It only takes one of the 8 to cause a problem.
Go look up the engine specs yourself and you will see for yourself, they are very close to the same. I never made a comparison of a 1990 and a 2005, you did. And the filter likes to tighten itself up. This surprised me, I've never used 5W-20 in my life. I seriously doubt the tolerances are much tighter at all.
Also, what makes you think the engines are lasting longer than they used to? This surprised me, I've never used 5W-20 in my life. As someone else pointed out, Dodge's Hemi is very particular about it's oil grade. Unfortunately, many car makers consider even a quart every 1000 miles normal. There is nothing wrong with that oil. The firing order of the spark plugs is 1-3-7-2-6-5-4-8.
I am however ignorant as to 'how' many parts work. I don't dispute your specs, but they have no relevance to my statement. My 2005 Ford F150 with Triton 5. I rebuild Chry diffs 10 to 1 compared to Chevy and about 10 to 3 on Fords. Testing has validated this viscosity grade can be used in many previous model year vehicles. While not part of the basic engine itself, the windshield washer reservoir holds 4. A 1990 and a 1957 engine design hasn't changed very much at all and I am willing to bet the clearance specs aren't far off either.