Quote Originally Posted by 76GMC1500
The most important thing is to keep the revs up, 2000-2500 rpm for the first 30 minutes of run time to keep plenty of oil flowing to the cam. The rest of the break-in depends on the rings you used. Chrome rings take the longest to break in, followed by ductile iron. Moly rings break in the most quickly. If you used moly rings, it will take about 300-500 miles for the full break-in. Change the oil at 500 miles or so, I waited until 1200 to change my oil. It's not really a big deal. Most new engine oils carry an API SM grade. The new generation of SM oils doesn't have the zinc additives that flat tappet cams need to survive. The only SL oils still for sale are the heavy duty oils for diesel engines like Chevron Delo 400 and Shell Rotella. It might be a good idea to run Delo 400 15w40 for your initial break-in. If not, your GM dealer sells an oil supplement with zinc for flat tappet cams. I broke my engine in on Castrol 10w30, an SM oil. This isn't that big of a deal, either.
The Titanium Nitride or the Plasma moly rings are harder than the Chromium Nitride rings.