So you use all 4 idle screws equally? This is what I thought as well, but there are many who say block off front carb/ bottom idle screws and only idle the rear carb. With the ability for better idle fuel distribution at 4 corners vs 2, I wondered what the reasoning for that was...….
Start with all four screws out 2 turns,then start at the front and turn the first screw in until you start to lose rpm's then back out 1/2 turn,do the other front then go to the rear,same thing.If your idle speed changes you will have to do it again until it idles at the correct speed. If it is a original 2x4 barrel application,both front and rear carbs have idle circuits,they are there for a reason,why block them ? This runs like a clock,850 rpm at idle,15 in vacuum,couldn't make it any better !
