How many miles to break in new rod/main bearings?

[joesushi]

You never need to be EASY on an engine. The point of rebuilding engines is to replace seals, correct loose tolerances, and get more compression from seating new rings properly(arguably the most important part). You seat rings properly by throttling up in rpms and letting off (keeping it in gear) revving down creating vacuum, and flexing the rings up. Then do the opposite and create a little boost and flex the rings down. Your freshly honed cylinder walls will sand away at your rings creating the best possible compression.

My engine runs great after beating it like a wife since day 1 and thats about 10k miles. My first rebuild.