Carb Tuning with AFR Guage

Hey guys I need some help. At wide open throttle the car is too rich at lower and mid RPM ranges. Like 10.5:1. By the time I hit 6,000 RPM its much better at like 12.0:1.

This is a 360 with a procharger and Holley HP 750 converted to blow through. Running 10 lbs of boost.

What would I need to change to make it go more lean at lower and mid RPMs but not change the high rpm AFRs?