First off, I've only rebuilt one engine, and assembled one other. I have had quite a few years since then to read and ask mentors and learn about building engines and I always recollect the essence of breaking in an engine. NOTE:"Full" rebuild done in well equipped machine shop at local college--did any/all required machining myself. Very neat experience, indeed.
I have come to understand--either correctly or incorrectly--that camshaft break-in is tantamount. There is also a method for "setting" piston rings. These two methods are done upon immediately firing the engine and immediately driving the car, respectively.
However, there seems also to be one more step of break-in, more of a rule-of-thumb "grace period" type break-in for the engine as a whole unit. Typically it goes something like, "drive 500 miles, then replace oil/filter--do not exceed 3/4/5000 RPM;limit/avoid use of Wide Open Throttle" That is a pretty general description.
So here we have a minimum mileage requirement(most say 500-1000 miles), AND we have a performance limitation: most tell you to not push engine hard, and keep RPMs low for duration of initial break-in mileage.
So what did race teams do when they needed to race their engine like mad men the next day? I don't care if Traco or Bartz built your engine, or if it was Al Richards and his buddies
What was the procedure to keep engines alive? I have a funny feeling Donohue didn't exactly take the Penske Camaros out for a 500 mile stroll the day before a big race with a new engine, nor did Traco do it for them.
So then what??
Did Traco/Bartz/independents just not care? I remember an article stating Penske engines were only used for a couple races before a complete teardown. Did they just break in the cam and then send it off to be spun at 7500 for eight hours and just say "screw it" to engine break-in? Is engine breaki-in only important to ignorant little kids like me who only drive on the street?
Thank you to anyone who may have insight, and apologies for my long-winded-ness.