Unexplainable Transmission Stutter... help?

Just pull one plug and see if its black and sooty.
I have seen this before after a cam swap and AVS2 carb. Sounds like an ignition misfire around 2k rpm but will idle just fine. Its because when you open the throttle blades the vac drops and the carb switches to the power circuit(or whatever it may be referred to as). Bigger cam means this happens earlier and you need to tune the carb to get them needles opening when you need them too, not at low rpm. So heavier springs make them open later. These are the two plates you swing open on the top of the carb. Very easy to change out but you will need to buy the calibration kit to get the springs.
Im not saying this is your problem but its worth looking into.