The converter flash stall all depends on the specifications on the cam (duration @ 0.050 and gross valve lift.) With more lift and duration the power curve of the engine changes. There are other factors that play into this as well. Load from tire height, gear ratio, weight of the vehicle, CFM of the carb, atmospheric pressure, and cubic of the engine.

A converter is the void between the automatic trans and engine. Where a manual has a clutch, pressure plate, and pedal, the converter has internal parts that work with fluid that allow a certain amount of slippage. A converter acts as a fluid coupler as well as a torque multiplier.

If you decide to add a high performance cam, we would look at the whole application, and then decide from there. If the cam is high duration, and you run a stock converter, you will not have enough slippage. The power band of the engine has changed and this could result in stalling of the engine when put in gear.