Roller cam and lifters doesn't need much Break in but rest of engine often does.
Basically drive normal first 250 to 500 miles and avoid floor the gas etc.
Hope you use cheaper oil. Anything cheap 5w-30 w/ API rating. (SJ SL etc.) or the Poland/EU equivalent ratings.Why?
Rebuild engines can have problems besides "Breaking in" a motor and may need to dump after 1 to 1000 miles because of coolant leaks, bad whatever leaving metal in the sump, etc.
Set timing as directed by VECI label etc.
You need ALDL A-B shorted so can set base timing on any ECM w/ HEI. W/o that ECM control makes setting timing impossible.
If you install the dist... get #1 plug to be at/close to TDC after compression.
Ever then likely won't start under slower turn the dist one way or the other then set timing as list on VECI label on deck lid.Warning:
Do not crank too long. Starter and everything will heat up fast and you'll need a new starter etc. likely soon. GM spec 30 sec ON max then 2 minutes or more Off.
------------------Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)The Ogre's Fiero Cave
[This message has been edited by theogre (edited 10-08-2019).]