I am running a TC3 in our VTA class and I just got a 17.5 setup for it, I am having problems getting the 3.5 to 3.7 gearing. The largest 64p pinion I could find is a 56 tooth which calls for a 79 or 80 tooth spur, the smallest I could find is 88. anyone know where to get a 79 or 80.