changing gearing
 

i have a OS .18 in my rusty and the engine is so big there is no room to move it side to side for adjustment, on it now is a 20 tooth CB and 72 tooth SG and its to low geared and i want to make it higher so if i get a 22 tooth CB what tooth spur would i need so i can line it up and dont have to move the engine any on the mounts would, i thought maybe just get two teeth smaller on the spur and it should line up but since the diameter of the spur and clutchbell are way different 2 teeth smaller on the spur might not be enough