Holley 750 stalls while hard breaking

What i also did with no success till now was sticking 2 rubber hoses on the vent tubes, but issue didnt change.

I will try to lean idle mixture now, so i will try to go for highest vacuum and then go 1/4 turn or so lean.

The jet extensions seemed to help a lot of people, also read you need another float or turn the one you have upside down?? what you think about that:
AED Performance 5896 AED Rear Jet Extension Kits | Summit Racing

Or better those:
Summit Racing SUM-200150 Summit Racing® Jet Extensions | Summit Racing

Thanks for your help!