when building other engines it was alway dependant on the engine. but
for most you wanted an an initial run in of about idle speed to ensure
no leaks or other problems  for about five to  ten minutes.  then a
drive around for  about thirty minutes  that had no  consistant rpm
rate with normal accel and decel of the engine going no  higher than
about 4k.  recheck compression, timing, and torque specs as well as all
connections  to cooling  and fuel and plugs. try not to go above eighty
percent of whatever the redline of the engine is for about five hundred
miles.  this is what was taught to me  by engine builders as  i grew up
many years ago.  i have seen not real reason to change it. as for the
under fifty five for a  thousand,  look at what i was taught and it
just may apply to those particular  engines depending on gearing.  the
roadhaus leaving denver  with that engine in normal shop break in, was
already probably  at about300  miles  equivalent.  due to the nature of
  hiway  25 he probably  did not reach any appreciable speed for  about
another 100 miles.  with that years tranny  he probably was not
redlining until  ninety five.
jimt
On Tuesday, Oct 15, 2002, at 18:11 America/Denver, Bill Marshall wrote:

> Jay sez
> <<Bob Donalds says under 55 for the first 1000 miles!>>
>
> While I agree, wouldn't a max RPM be more exact?  Breaking in my
> Tiico, I
> kept it under 2500 for the first 1000 miles.  (55 in second gear isn't
> good
> either.)
>
> I've also heard of folks saying "5000 rpm for 2 minutes, and it's
> broken in."
>  Anyone else heard that one?
>
> Bill Marshall
> 85 GL Tiico "Pandora's Box"
> Bradenton FL
>