When I had my bottom end rebuilt (When I say rebuilt I mean only new pistons and some ACL rod bearings), my mechanic told me to drive normal but try not to keep the rpm's at the same spot for a long time, no highway driving on cruise control for example. He said vary my speed as much as I can, go up and down through the rpm range, and it was OK to take it to redline once in a while. There's a few different theories as to the best way of breaking in an engine, but that's what I did.