Engine Stall when heavy braking

[thunderbolt]

You have a lot of carb for a 289. With a 750 you will not see the throttle response of a 600 because of the volume difference. However the bog issue could be several things like other people have mentioned. Does it happen all the time or only some of the time, hot or cold? You may need to adjust the accelerator pump to give you the proper boost of gas when you step on the gas. I think a bad float level might have an effect here too as well as maybe being the stalling problem. You don't have power brakes do you? If so it could be a bad booster causing a vac leak when you hit the brakes.