Don't worry about overtightenting a Dana 60 pinion nut in the car unless you have a 3/4 inch or one inch impact air wrench with a very big air compressor
As already said some of the FSM show using 250 Ft lbs on them, others show 150 Ft Lbs.
I use a 3/4 inch drive breaker bar with a 8 ft. long cheater extension on it and then jump up and down(220 lbs weight)it until it quits getting tighter(that is with the rear end out of the car on the shop floor
I am one of the low experienced rear end guys so I use the FSM procedure to check the pinion bearing preload as well as pointing the pinion straight up into the air when checking the rotational torque both ways with a 1/4 drive inch pound beam type torque wrench
Once you get it within factory specs . you have to remove the pinion nut and yoke to install the pinion bearing seal
BTW, I have a stock of non lock nut pinion nuts(grade 8 extra long
) so I don't use the lock nuts that come with new gears