Need help with ultra lx pro and os .21 rz v99
 

I have an ofna ultra lx pro that I recently bought a motor for. I am putting a os max rz v99 in it. The motor is not the sg style crank. It has the short shaft. My problem is that I need it to be moved back because the diff gear and the cluth gear do not line up. I can take the spacer out from behind the flywheel get the gears completely on each other but they are only flush. The guy at os said that I should not take the spacer out because of the balancing. Is there a company that makes motor mounts to go further back or does someone have a suggestion. I hate to run it with the gears not centered. Hopefully someone will be able to hlep me. Thanks Brent