[thardin]

I have always been under the impression that the 500 or 1,000 mile break-in periods were a precaution for "assembly line" produced engines. If a motor is properly "blueprinted", then all of the proper clearances are checked and double-checked during the motor build. The production line simply does not take the time to check every clearance. Running a long break-in period allows the motor to "wear-in" to the proper clearances without damage caused by tight parts heating too quickly (over-expanding).

In a blueprinted motor which is self built or built by a reputable shop, you will typically break in the cam, check for fluid leaks & temperatures, and go straight to dyno pulls (or the race track). You may want to watch out for some of the big crate engine producers that really pump them out!

Personally, sounds like your builder is a little conservative. Some of my best motors have been run hard "right out of the box". I only believe in a break-in period for mass produced vehicles.