And a question for you. This is on my Quick Fuel 650 DP on my truck. 75 F250, 400 with old school Crane Fireball. 228/232 @ .050 on a 108. It was RIGHT AT 9:1. it runs great, but it stinks at idle and I know it can be better. It has 31s front and back for IFRs. I tried putting in larger idle air bleeds, but that did little to nothing, so I put the stock ones back. I think I went from 70 to 74 with zero change. So I "figure" changing the emulsion bleeds will make the difference. It's a four corner idle carburetor. Idle timing is about 44 degrees with the vacuum advance on full manifold vacuum. That actually helped some, but it's still overly rich. Transfer slots are square. Secondary blades are cracked JUST ENOUGH so they don't stock closed. Would you change the secondary idle IFRs too? "How much" do they affect idle mixture? I tried some 28s I had already and that made a little difference, but not what I hoped, so I put it all back stock so I'd have a baseline. I have some 26s on the way.