Alot of it has to do with cylinder wall finish and the material of the rings. I have run several new engines on the engine dyno, and everytime its the same process: Fire it up and set the timing; Let the engine high idle a little to get some heat in it; Make a short pull to 4-5000 rpm (depending on the max rpm); If everything looks good, make the next pull to peak.
My engine literally went from never being run, to 8000 rpm in about 20 minutes time. Usually after the third or forth pull, depending on the ring material and cylinder wall finish, you can see the engine making more power due to the rings sealing. This is on a race motor though, a street motor might take a little more time.
My advice, is to take only the advice of your engine builder. He knows your engine better than anyone.
Andy
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88 coupe
91 LX NMRA Pure Street 5120
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