Holley carb help

I need some input guys. I have a 466 with a Holley 850 DP. No choke. Also no power brakes.
The problem is I live on a fairly steep hill and when i slow down suddenly or come to a quick stop the car want to stall.
I dont think my secondary bowl is dumping fuel into the carb because my carb has the plastic vent baffles in place. I have the floats set to the baseline setting to where fuel spills out of the port when you shake the car slightly.
Someone suggested backing off my idle mixture screws an 1/8 turn but i dont know what this would do to help. My car idles around 900 rpm. Any help would be appreciated. Ive been dealing with this for a while now but am getting tired of it.
Let me know if more info is needed.
Thanks Bob

Raise the float level.
Turn the front needle/seat cartridge CCW about 1/3 turn

Fuel uncovering the front jets.

I bet more Base timing will help. Plus maybe a hair richer on mixture screws about a half turn out on front.

Thanks for the help guys . Im gonna try one thing at a time and ill let you know what helps or hurts!
Bob