[Mr. Wyndham]

Your friend is partially right. (I didn't read that link, but rather am using infinite wisdom passed down from GMHTP magazine )

The breaking-in period isn't a huge issue as much as it was. However, it still exists (the need for a break-in). How long you take is up to you. They advise ~500 miles, I think. The reason is to seat the rings (like said above). And city driving is preferred to do that. Because a constant rpm is only going to seat the rings at that speed, not the rest (over-simplification). Opening her up once of twice isn't going to kill it. In fact, it may help out the break-in process.

Also - as I think was mentioned above, get an oil change earlier than you're supposed to. Because the first round of oil is gonna get REAL crappy, real fast with all the wear on the brand new parts (mainly the rings).

So: change the oil early. Don't go road racing for AT LEAST 200 miles (imho), and vary the revolutions (minimize highway driving).

Hope that helped.

EDIT: I just read the link posted up...and although technically it's the same thing (motors and all) I'd rather not rely on guides for BIKES (and other small vehicles like that) to break in my CAR. (call me picky )

Here's the GMHTP article I was referring to. Don't want any of you to think I'm pulling this stuff out of thin air.

THE BIG BREAK-IN

OK, so it runs--good work! But your big-cube engine isn't quite ready to impress your buddies on joy rides, much less hit the local drag strip--and we're not just talking about making sure the tune is dialed-in (more on that momentarily). Anyone who knows the least bit about automobiles has heard the shpiel that new engines need to be "broken in." Going through this procedure ensures optimum power output and long component life, but what exactly is going on here, and what's important to know for the Gen III?

During the first several hundred miles of operation, the metal parts of the engine "mate" to each other. While advances in technology mean that engine parts are manufactured to more exacting tolerances than ever before, the microscopic uniqueness of any one piece of metal that comes off of the assembly line or out of a machinist's cylinder honing machine continues to endure. Think of this mating like the last step in machining: all surfaces that contact one another "wear" or "finish" each other to the point they'll operate at for the rest of the life of the engine. We want this initial wear-in to occur, but if we try to get it to happen too fast, the engine parts will instead wear out prematurely.As far as GM small-block engines go, allowing flat-tappet lifters to properly mate with the camshaft lobes was a huge concern back in the day. This necessitated special lubricants, and also required the engine to be spun above a minimum rpm for the moments following initial start up. Happily, those days are ancient history, and thanks in part to this advance, no elaborate, "ceremonial" break-in is required for an LS1-based engine. But our beloved V-8s still have important parts like bearings--and most significantly, piston rings--that require a wear-in period to operate properly.

So, how to go about this? We spoke to Mark Chacon, Lunati's East Coast Regional Rep., about his thoughts on this issue. "As motors are breaking in, and in regards to piston ring seal, they want a constantly changing engine rpm environment. This is why city driving is generally the optimal condition for any motor break-in. The worst thing that you can do with a new engine is to put it together, fire it up, and then head down the interstate with the cruise control on. While a little bit of freeway driving is OK, certainly for the first 500 to 1,000 miles I would try to avoid long trips or periods where you're operating at a constant engine speed," says Chacon.

OK, so staying at any one engine speed is bad, but this isn't to say you can go take your new engine to six grand the first time out. On the contrary, restraint must be used to keep engine speeds and loads reasonably in check. "Don't go out there and just hammer through the gears all the time; you need to be a little more conservative about how you drive the vehicle. A varied range of rpm usage, combined with keeping it easy on the motor, allows the face on the ring to do a better job of seating to the cylinder wall," says Chacon.

The type of fluid used during break-in is also important. You may have heard that synthetics are "too good" to use during the first miles on a new engine, and this is true. The main reason for this is the piston rings, which as we have said need time to seat to the cylinder walls properly; if they don't, horsepower and efficiency will be left on the table thanks to reduced cylinder pressures. Mark Chacon elaborates: "The ring face must have ample time to break in to the cylinder wall finish, and running a conventional oil for the first 1,500 miles or so will aid this. Ring seal needs to be firmly established before synthetic is introduced into the motor, and one of the reasons the factory LS1 has such a heck of a time with ring seal to begin with, in my view, is that many come from the factory with synthetic oil in them. Once you put synthetic in, what you've got is what you've got, and the rings may never really wear to the cylinder walls. Of course, feel free to eventually switch to synthetic because of its better properties, but make sure the rings have seated fully first; short of using a cylinder leakdown tester, mileage accumulation is the only way to tell whether this has occurred."

As engine parts wear in, more small metal particles are being cast off into the engine oil than would usually be expected. Therefore, keeping the engine oil clean during the break-in period is essential. In furtherance of this, be sure to use a high quality, high capacity filter that can capture very fine particles. As to fluid change intervals, a good rule of thumb from Lunati is to drop the oil after 100 miles to get the initial bearing cast-off material out of the system. Then, change the oil after 500 miles, and again after 1,500 miles have accumulated, from which point forward you can follow manufacturer-recommended change intervals and swap to synthetic oil if desired.Stick to these simple driving and engine oil maintenance tips during the break-in period, and you will help your stroked LS1 live a long, happy life under your GM performance car's hood.
http://www.gmhightechperformance.com...ild/index.html