Whos running over 700whp on an 8.75?

GTX JOHN said
I have been doing this a long time = My vote is to put in the
Dana for sure. I used to break plenty of 8 3/4 stuff with 3400 Lbs
with a 4 Speed and 550 HP!!

Yup! Amount of power/torque vs weight/mass being moved coupled with the shock load, manual or automatic.

Do you feel it would have held up measurably longer at a weight loss of 400 lbs.?