So what happens if you keep the old /6 rear end after 360 swap?

I have a feeling I may run out of cash doing this...
So, what would happen if I kept my old stock rear end in (From the /6) after the 360 swap?
Would I just not be able to really stomp on it with out breaking something, or what would happen? Thanks!

I'm not even going to read the thread. I'll answer it in one word.


BOOM!