So I purchased my 2010 Silverado ext 4x4 last week and have been googling the correct break in procedures since it's my first new vehicle. What I've heard most is baby the engine for the first 500 miles then after that up to 2-3k miles drive at around 35mph and floor it to 55mph. Well I've been driving it a lot so I can reach those 500 miles, but in this small town I live in I've only hit a little over 150 miles in the week that I've owned the truck, and I work locally. Well, today I'm taking it for a road trip to the beach and will be doing some high speeds. Is this bad for the new engine? I've been avoiding hard acceleration for now even though I have a heavy foot, so it's been irritating. The beach is an hour and a half away, then going to Jersey afterwards, then back home to NY. I'll probably put close to 300 miles on it by the end of the night. I've built engines before and understand why high revs are important to let the engine heat up and expand the piston rings to prevent blow-by and burning oil, but I'm not sure if I'm gonna overwork the rod bearings and new gaskets.

 

From the owners manual:

New Vehicle Break-In
Notice: The vehicle does not need an elaborate break-in. But it will perform better in the long run if you follow these guidelines:

• Keep your speed at 55 mph (88 km/h) or less for the first 500 miles (805 km).

• Do not drive at any one constant speed, fast or slow, for the first 500 miles (805 km). Do not make full-throttle starts. Avoid downshifting to brake or slow the vehicle.

• Avoid making hard stops for the first 200 miles (322 km) or so. During this time the new brake linings are not yet broken in. Hard stops with new linings can mean premature wear and earlier replacement. Follow this breaking-in guideline every time you get new brake linings.

• Do not tow a trailer during break-in. See Towing a Trailer for the trailer towing capabilities of the vehicle and more information.

Following break-in, engine speed and load can be gradually increased.

 

In The Long Run the engine will perform better. Also you have a 100k warranty. I wouldnt worry to much about it?