interesting enough, there seems to be a lot of people (not really sure I am a fan of this ideal) now saying that there isn't a need for a "break in period" and after running for an hour or so to make sure there are not any problems right away, they say to immediately start running the engine hard as it will wear in everything a lot faster... and is (in theory) better since everything is not taking as long to wear in. my concern with that is that if there is a problem, then its probably going to destroy something (or a lot of somethings). their argument is that if it was put together wrong, then it would show right away and would still cause damage and would need to be torn apart to be repaired anyways..
This may be different with a Mod Motor, (and boost) but when i broke in the 347 in my Mustang, I went thru all the gears under acceleration (not real hard) and also let the engine drag itself down, while shifting down thru the gears and my rings were seated in no time, the constant pressure to the rings even on decel is beneficial.
347's are known for being smokers because the oil ring meets with the wrist pin hole, after my initial break in, it never smoked. I used Brad Penn break-in specific oil, to help guard the camshaft during break-in.
After my initial break in, i changed the oil immediately, then 300 miles, then went directly to Royal Purple. I never took it easy on that Engine, except the first break-in because i was afraid to hurt the camshaft. I set a soft rev limiter at 5k during the first 500 miles, and after that i removed it, That car had no problem eating corvettes, and making the owners flick me off when they finally caught up.
The only initial problems i encountered was the MSD distributor was shimmed improperly from the factory, and chattered loudly. I also had to swap out a set of roller rockers because the cheap set i initially used started to walk and rub the studs, after that it was perfect.
So i approve of the drive it like you stole it break in procedure, like you i was skeptical, but i was also excited to experiment and prove traditional theory wrong. Remember materials and procedures were far less advanced when engine break-in procedures were created for traditional V8's etc.