Hey i just got a new carb for my truck (Holley 600) how do i adjust the idle mix screws and the air-to-fuel mix screw?? I can't seem to get it right

 

First get it to idle with the linkage adjustment. Then turn in the air screws all the way in, not too tight and twist out one full turn. The richer the idle mix, the blacker your exhaust will smoke. Black smoke = rich mix. With my experience you want to be right on the edge of the black smoke / no smoke edge. Slight black smoke runs better for my set up at thetime.

After you get that set, you play with your jets until you run too rich up high s then slowly lean out until you feel power los and go back up to a richer jet set.

With my short experience, you need no power valve, a big shot of gas from the accelerator pump(either a bigger cam for the pump or a complete bigger pump) to eliminate throttle response lean out. Then the wide open should be done at the track when you know only the carb needs tunning and play with the jet sizes. A good thing to keep in mind when tunning jets to track times is keeping everythig the same but your jets and try to keep a record on paper to keep it orginized.

 

After trying this procedure I squeezed out a 9.5 in the 1/8th with a stock port 12a, header, and a 600.

Soon will be testing my street port.

 

Nice....keep us posted!