edelbrock 1405 problems

Hi Guys and Gals.
340. Flattop. Aluheads. 2 plane intake. 10,5:1 comp. street cam hydraulic very moderat. Carb set at nr 3 in the chart.
Goes perfect at idle, light throttle, transition @ ca 0,95 to 0,97 at lambda. But light stumble to WOT. Not tested next hole on acceleratorpump yet. Then lean about 0,99 lambda at WOT all the way to 6000 rpm. Second main +16% according to the chart in the book.
Tested a 800 cfm edel and that pulled strong all the way. Same setting as the 500cubic motor it came from. Tested fuelpressure and all good from 800-6000 rpm
What am i missing?