Not correct at all. I did a direct swap (1.40 FZ to 1.40RX) years ago and he OS delivered FAR more power. And on 15% as oppossed to 30%.
It's a direct swap the only change was the nose ring as mentioned plus of course you'll have to make arrangements and mount a giant 2 stroke muffler and some right thrust tweeks.
I had the FZ definately proppped with a 16x10 and the RX from what I can remember, a 17X12 and 18x10w.