Running these motors in properly makes all the difference, I rev them high but never with full throttle or for prolonged periods, also never lug them up hills, get into a lower gear and keep revs up while using low throttle.
The ideal running in regime - you need the revs to free things up and make sure there are no high spots but not loading the engine by giving it too much throttle .
It was always suggested to me that the actual revs are not a problem within reason as long as the load on the engine is not high , so running along on half throttle down hill at near max speed is better than lugging up a hill in top "keeping the revs down" !.
Having said all that, there's a school of thought that recommends shorts bursts of near-full throttle to force gas behind the piston rings, making them expand and bed them in to the bores. They say that failure to do this leads to cylinder bores and rings not bedding-in properly resulting in lower compression and performance later on.