I read in an old repair manual the the best way to break in a rebuilt (overhauled) engine was to do ten 30-50, full throttle runs in third gear. Most cars were 3 speed manuals when that book was written.
I have used that technique and as far as I can tell, it worked. None of my rebuilds ever burned oil.
A lot of unqualified people want to be writers. There is a lot of pure trash said about cars. They can bother more people if they write about it.
@keith Even new car manuals often advise full throttle acceleration from time to time to speed up the break-in process.
Opening the throttle up during the break-in process I don’t have an issue with.
What I don’t care for on that site is:
Apparently that guy has never seen an engine seized due to cylinder temperatures.
Guys, the poor guy isn’t here to defend himself. I agree that his site is bogus, and I personally think the formatting is the worst I’ve ever seen, but jeeze, he DOES have nice teeth!
You can buy nice teeth but intelligence is not for sale.
Nice teeth that are your own, take many years of planning and care, much like breaking in a car. IMHO, the care and feeding of a car and it’s longevity continues long after it is officially broken in and minimizing wear is an ongoing process. I will take a car driven sanely over it’s life then one broken in perfectly then driven by a fool he rest of the time.
And to add to dagosa’s post, one that is properly maintained.