Well, I ordered an IFR kit from Summit. The carb is specd with 46's from the factory. Swapped them for 52's. No change. Swapped them again for the largest in the kit . 59's.. seems to be masking the condition slightly. The car overall is running excellent other than this lean condition when on the brakes. Is this just something most guys live with with these types of carbs ? My old 850 double pumper didn't seem to have this problem, but I never ran that combo with a wideband O2 sensor either. .. I don't recall it stumbling or stalling while braking but,, like I said... totally different combo.