Conversion 25 hp to 35hp

[mxhopser]

I have bought a 1996 Johnson 25 hp (type BJ25KEDQ / serial G 04117295). In the part list I saw that for this type 2 carburators are available - one with 25 hp and one with 35 hp which have the same parts instead of the orifices.
Does somebody know which parts I should order addional for a conversion?
Any help would be appreciated! Thanks.