If I were breaking in an engine I personally didn't build/blueprint myself, I'd be a little leary as well.
There is no RULE per-se, but if the clearances are right, there is really little reason to baby the thing, -as like MGW stated, roller cam, moly rings, etc.
The initial oil changes are a given, -it is always recommended that the oil be changed out in the first 100 miles, then 300, -etc.
I ran mine nice for the first 100 or so miles, -then changed the oil and LET 'ER RIP. I had no issues matting the pedal and rowing through the gears shifting at 4 grand, -even with only 150 miles on the clock. :thumbsup:
Like several others have said, -if there is something amiss in the assembly, or a bad part, it usually makes an appearance in pretty short order after the initial fire is lit.
Break it in like how you are going to use it every day.
My .02