Originally posted by 76GMC1500
Some say to use non-detergent oils like straight 30w, but I see no reason to do it. I just broke in a 350 Chevy on 10w30. I ran it between 2000 and 2500 rpm for 20-30 minutes. I tried not to lug the engine down by manual shifting it some, and didn't run it under sustained heavy loads like seen on the freeway. I did run it at full throttle for a few seconds at a time after the first few hundred miles. I have about 800 miles on the motor and haven't changed the oil yet, but I used a detergent oil. It will get new oil and filter around 1000 or 1200 miles.
Shoulda changed the oil after that initial 20-30 minute run to remove any intial shavings, or at least no later than 100 miles.

If I were you I would change it NOW. Don't wait any longer.