torque convertor

Hey Guys. Just got this engine, and I am trying to mount the torque convertor, but the bolt will not go into the center of the drive shaft. It's apparently a M10 bolt, or so it seems... But we cannot figure out the pitch of the threads. We have currently tried 1.25 and 1.50 threads...

i have a Trisport TS-110 i am just putting it all together and its almost done i heard they came from factory with a torque converter.. i currently just have a belt driven clutch running to the pulley that was on frame when i got it..i figured it should work to get it riding finally but...

Wondering if anyone out there knows why one would want a 20 series vs a 30 series. 30 series set up is easier because of the asymetrical design and also has a higher top end ratio. They are both rated for 8 hp. I would assume that a 20 series could handle more hp before slipping than a 30...