I've had several factory 8.25 rears in AHB Diplomats that I've put in a warmed up/heated up engine. Mine have always held up well. I put 60k miles on my first one with a MP 360/300hp that was pushing 400 lb/ft torque. And this is after the car was used as a police car so the rear end had plenty of miles on it. I had 2.92 and then 3.21 gears and 235/70/15 on factory rims. My current one has a stroked 408 that dyno'd on engine stand at 469hp and 528 lb/ft torque and it's held up perfectly. Same tires and a 3.21 rear gear and sure grip. I don't beat my cars but I certainly enjoy a good punching it now and then and a little tire smoke occasionally. As written, if you aren't running fat slicks and making a bunch of hard launches you'll be fine. I think the 8.25 is underrated.

Also if you find one out of a police car it will have the setup for the larger 11" brakes.