Sounds more like the seal is not installed correctly and is causing to much friction to turn, rather than to much torque on the bolts. There is a rope seal (wick seal) installation too. But you can also use a steal rod to ensure the seal is pushed into the grove all the way. I'm not sure how you get the top half in without taking the crankshaft down. I have not put a rear seal in a motor unless I had the engine out. I know you can do it with the engine in just seems easier for me to pull the motor.

Blackcloud
1940 Chevy Pickup 235 inline six