ok my 62 bus is a 6volt model, and I have fitted a beetle straight axle gearbox to it, i'm fitting the newly rebuild 1500 sp, i have 3x 12v 200mm flywheels kicking around I thought id fit one of those along with a 12v starter, but the starter does not go far enough into the bellhousing by 5mm approx. I know there are different thickness bushes but with no bush at all it still does not go in all the way, the 6volt starter does though?? are there different types of 12 starter motor for beetles bays & splits?

help!!