Start with the mixture screws on all 3 carbs out 1 1/2 turns.Put your finger over each air bleed and adjust the screw for that air bleed in or out so that when you cover the air bleed the idle does not change. Last one I set up ended up at 1 5/8 turns on all 6 mixture screws.
1 1/2 turn out for all 6 mixtures seems bit much I don't want to wash the cylinders out. I will try by turning them out another half turn and see what it does.
It's not too much. And thats only the starting point. You adjust further by covering the air bleeds and turning the mixture screws in or out til you can cover an air bleed and the car's idle neither speeds up or slows down.. I read this info from Larry Shephard's 6 pak book years ago, and to me it also seemed like too much. But it was the thing that turned the corner for the 1st one I ever tuned. I thought I had jetting problems, a plugged center carb metering block, I thought I had to drill open the holes in the secondaries more, and none of it helped. But opening the mixture screws on the end carbs to be close to what the center carb wanted was the key. The car has to idle on all 3 carbs, and not just just a trickle out of the end carbs, either. Your nose and your eyes will tell you if its too much. So long as your floats are adjusted properly , 1 1/2 turns out on all 3 is the place to start tuning. Before you can adjust jetting, secondary diaphram springs, etc. it has to idle, and idle cleanly. It's counterintuitive, but it worked for me. If it were me I'd put the carbs all back to stock so I'd have a baseline and start there.
