My brother is having troubles hooking up a 700r4 torque converter to a 350. I am not near by and I have limited experience with the 700r4 (I am a t5 t56 or 200r4 person). He says the hub isn't fitting into the crank and thus preventing him to bolt the torque converter to the flex plate. The engine is a 2 piece rear main seal( an old 4 bolt) The transmission is supposedly an 85(but this may be questionable. He has tried both a 153 and 168 flexplate. My question is, what may be causing this? Are there different sizes in the torque converter? Please throw out every possible cause as I am unable to diagnose myself, and he needs help. There was a pilot bushing for a manual transmission, but I had him pull that. Any help would be appreciated.