Putting a new cam in my 360

I was always under the impression that you want to keep RPM ABOVE 2000 for 20 min not held at 2K for 20 min. You are supposed to rev between 2000-4000 changing rpm and revving as the cam is splash oiled from whats slung out between the connecting rods. I have never had problems with FTH cams and was always told never hold RPM steady Perhaps your rod side clearance is too tight? Those push rods were not getting oil, why?