that's a poulan 32, they convert like a ryobi other than the muffler(don't know if they are a direct fit as I don't have a ryobi apart to compare), I haven't ran either of the two that I have to know how much power they have.

as far as the kill switch, take the wire that went to the stock kill switch and put it to a toggle switch or push button, the other wire from the switch goes to the engine somewhere, it's just a ground, grounds out the ignition to kill the engine.