Without pressing the bushing out of the rocker arm to measure for sure, it looks to be about a 3/4" OD bushing. Certainly enough meat there to bore it. Legnth though on that spec...maybe putting two in side by each...
A needle roller....I wonder though...why...I know its a PIA to oil the bushing...but longevity does not seem to be a pressing issue with this part...or did I miss something?
Joe