What can a 7 1/4 rear take???

The key to making a 7 1/4" live is a limited slip. It also helps if you are running at least a 3.55 gear. What kills them is carrier deflection which causes the spider gears to **** and bind. When that happens something's gotta give and usually it's the spider gears although I have seen split carriers. numerically higher gearing lessens the side loads placed on the carrier by the ring gear and going with a Sure Grip gives you a stronger carrier. I ran a 3.91 geared Sure Grip for years behind a 318 and couldn't break it. It was a replacement for a 2.76 geared open that grenaded at 21000 in the same car.