As far as I'm concerned needle bearings in rocker arms are a PITA. Out of all those needles it's only the bottom 3 or 4 that are doing anything, the rest are there to keep the bottom ones in place. Those needles will wear the bottom of most shafts I've seen over the years which causes your push rod clearances to open up especially if this is on a street car. The worse thing though is one of those bearings decides to come apart, and they do sometimes, now you got needle bearings all over the inside of the engine. Whereas the aluminum or cast iron (mopar) rockers work just fine.