gears.

HI Can anyone help me on an issue which is can you put a v90 3rd gear as a 4th gear in a 4speed box v90 has 47 gogs and the prim 4th has 46 gogs I have fit them all together on the shift dog and they all seem to fit and work. But I wonder does anybody nos anyone who has done this and would it work as the zirri short 4th has 49 gogs you can see why I am doing this as I already have all these parts in the garage can anyone please help. Cheers scottie