Roller cam bearings

[SSDiv6]

Originally Posted by Todd Gross

The biggest advantage of roller bearings are that they do not need pressurized oiling. So in most V8's you are blocking off 5 oil leaks inside an engine.

The roller bearings still need some pressurized oiling; they do not oil by themselves and although there are claims oil splash is enough, I have seen enough damaged roller bearings due to lack of oiling especially on endurance engines.
If you have the right cam journal an lifter bore clearance, you will not have to worry.
Yes, they are known to create harmonics issues and it shows in Spintron testing.