Can i drop a chevy 350 in a jeep with the stock ?

you can do anything you want to do, the question is what makes the most sense. you can most certainly put a chevy 350 in a jeep, it's been done many times. you can use the stock trans however ir will not bolt to the engine, you will have to use an adaptor plate, but as i said its a question of what makes the most sense, what makes most sense behind a chevy 350 is either a th350, th400, or best off a th700r4 or 4l60e. you will then want to upgrade the axles as the housings are the weak point. makes no difference if the jeep was originally a 4 or 6 cylinder, and yes, you can put a 6 cylinder in a jeep where a 4 cylinder once lived, the wiring harness is different and so is the computer and the frame mounts as well as many small parts but yes can be practically done.