What can the 7.25 handle?

I realize I am pushing my luck, but I have been driving a 350hp 5.9 Magnum with a 5 speed OD in front of an original all stock 7.25 for months and have even done block long burnouts with it.
Yea, they are not made to stand up to that, but they are not quite the total sissy everyone who isn't spending the money says they are either.
They came out behind 318's for frickin decades, and are still out there running and driving every day 40 years later.
Being behind a 125hp diesel with an auto would be a breeze for it if it's ok and not already going out.

That said, if you can put a better stronger rear in it why not do it?