There are some lists on cbrforum.com of what exactly will & wont swap. My F3/2 has many mixed parts on it. I went the F2 way, so I didn't have the F3 carbs and extra crap to mess with. Another F3 I rebuilt I used the F2 carbs as well with the F3 engine with no probs. Good luck to you and hope to see some pics of your progress!