Well just look at the name. RX-7 means Rotary Experiment #7. So since it has a 350 in it that would make it what?.... a 350-7? lol
Ok bad joke but anyway. Nope. Its not an RX anymore. More power to you if you want to mutilate it and put a piston engine in it. Just send me your old rotary so I can make it kick your pistons tail.