Do a search on "engine break in", you should find a couple threads that go into detail on how to break in the motor.
Got this from speedster, Modern engines are nothing like their counterparts of a decade or two ago. Bearing and ring materials are completely different and the level of finish on the crank/rods and cylinder walls is excellent. Valvetrains are also ready to go. These are roller drivetrains so varying the rpm isn't necessary like flat tappets for oil dispersion and tappet rotation.
The professional builders I have dealt with warm up the motor at 1,500 - 2,500 rpm, check for leaks and set the timing/fuel ratios. Then they change the oil and filter to get rid of any residual dirt/particles/break-in lube.
After that, they fire it back up, bring it to temperature and hammer it for as many dyno runs as necessary. This is from personal experience and there are probably factory GM types that know a whole lot more that can chime in.
Basically you are probably pretty safe in whatever break-in method you choose. GM tests these things to failure to make sure you don't...
If you want to be super safe, get to 500 miles to cover the drivetrain and brakes. Matter of fact you can do the pump and fade method to break the brakes in quicker. Change the eingine oil to get out any residual crap. Then fire it up and hammer it !!!