I know this has probably been asked over and over, but I didn't find any threads talking to much about 55-64 Chevy rear axles as far as durability. I am getting ready to put a motor and trans in my sedan delivery, and was thinking about looking for a better diff as well. I don't plan on thrashing this thing, and it's just a mild sbc with a cam and some 461 camel hump heads... but I've been know to do a few burnouts and such! At the very least I was going to get one of these kits http://www.classicchevy.com/chevy-rear-differential-bearing-and-rebuild-kit-1955-1957.html and go through the rear end before I put it back in. If everyone screams at me to replace it with a 10 bolt or something maybe I'll bite the bullet and update it now instead of being broke down on the side of the road this summer.