Platinum Racing 1.1mm Oil Restrictor - Nissan RB20 / RB25 / RB26 / RB30SKU: PROGRB-11
Extensive R&D using the Platinum's own drag cars has shown that during one quarter-mile run an RB can spit out up to 4L of oil from the rocker covers into the catch can. Furthermore, 90-percent of that accumulative volume waste is a top end that’s over-oiled, let alone the oil that actually makes it back to the sump.
The only oil source to the top end is a 1x2mm restrictor, Platinum offers 1.5mm, 1.3mm and 1.1mm options perfectly matched to your set-up. Also available are blanking plugs to be used in an RB30 given the second hole has to be blocked regardless to meet with an RB25/26 head.