Usually torque converters have captive nut.
The one I'm working on has very short nuts and bolts.
Besides using thread locker,what are the safest nuts to use.
Thanks.

 

If it's an aftermarket converter that uses a nut and bolt your best bet is to put everything together and then measure the holes for the correct length. Use grade 8 bolts that are just long enough to go through the converter, the flexplate, a grade 8 lock washer, and a grade 8 nut. The bolt should have 2-3 threads showing once everything is tightened up...as clearance allows.

If you want pics I can take some...just let me know and I'll be happy to.