9" rear end on a 66 mustang

Ive heard good things about the 9" rear end and was wondering if it would be a good upgrade for my 66 mustang? Down the road from my apartment is a junkyard with a 1977 bronco. I think i read that in 77 the bronco came with the 9" rear end and i was wondering what i should look for in it as far as whether its worn out or not and is it a quick and easy swap or what all would i need to do to put it in as far as drive shaft, transmission, u-joints, etc.? Would the differential from a bronco have the right gear ratio for a mustang?

The 9" rear is a truly high performance part designed to take an incredible amount of abuse without breakage. Specifically, high HP drag racing in a heavy car, or heavy duty truck usage. The trade off for this abuse potential is weight, size, and HP to spin it. Life is full of trade offs, isn't it? In a '66 you really don't need all that strength unless you've installed a big block for drag racing. The 8" can be built to handle almost as much power but for a lot less money and requires less power to run it. For most of us, the 9" really doesn't make sense in a '66.

I have a 9" inch in my 66, I didn't add it, it simply came with the car when I bought it. The one thing you should remember is the rear shock plates may need to be replaced to accommodate the extra dimensions of the rear end. The guy who own my 66 before I had tried to modify the shock plates by drilling new holes and left them dangerously thin in my opinion e.g. almost no metal between the news holes and the old original ones. I upgraded to the 67 shock plates and the problems has been taken care, one issue is these plates will need to be purchased from a bone yard since they are no longer being produced. As for the bronco I have no idea about the rear end.