||As stated above, I dropped the oil after first start/warm up. Then after first drive dropped it again. Then changed at ~100, 500, 1000 miles.
My freshly rebuilt engine also had brand new turbos so I installed filtered oil feed lines (filters before the restrictors). Didn't want any break-in materials making it into my expensive new turbos.
Next time you break in an engine, remove the oil filter after first start/warm up, cut it open, and take a look. I did this after each of my first few oil changes. I didn't upgrade oil until they came out clean.
Dual GT30 inside