Both sides. I’m not sure on those metering blocks, but you may have to tap the lower holes to 6-32 to lower them. I have no idea why they all run the IFR’s up there. They really need to be in the lower position. I’ve tired my junk with them high and low, and my deal liked them up. Now, I’m thinking my tuning was off in other circuits, causing the carb to want the IFR’s up high. So I think I’ve corrected my tuning sins, and I have them lowered. And, unless it absolutely won’t idle correctly, I’m going to leave them down. The science behind low IFR’s has long been settled. And if you think about it, the science makes sense.