What are you trying to break in? The only part that should really require 500 miles is the clutch. As far as the engine, with the materials and techniques used widely 500-700 miles is not needed, especially on a roller cam engine.
I have read many different opinions on the subject but a lot of current builders that I have talked to say that the rings seat very quickly when moly are used.
I guess it all depends on what parts are used.......
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"I'm in the 82nd Airborne and this is as far as the bastards are going!"
93 Cobra, R302 331,canfields,T-76,TKO......sold
87 Coupe, 466, Edelbrock heads,Vic jr,150 shot 10.41@129.5...sold
2006 Honda 450ER .....new toy
Do you own a Torch Red FRC and tremble every time you drive under I75 on Hwy 60 and look in your rearview mirror? If so you are suffering from what is known as Cobraphobia.