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

The 7 1/4 is not as bad as some make it out to be. As others have said, the best thing for a 7 1/4 is a SG unit. But they are hard to find, and repair parts are even harder to find. There were two different type Sure Grips. Early clutch type, with 4 spider gears, and the later cone type with only 2 spider gears. The clutch type is the best. I have three 7 1/4 rears. A 5.13 SG, a 4.56 SG, and a 3.91 SG. The 3.91, I have been running since 1974 in my slant six cars (been in 4 of them). Just pulled it out in 2012, when the SG started slipping, and installed a 8 3/4. This rear has withstood thousands of 1/4 mile passes on slicks, in a 3200 lb car. The car 60 foots at 1.79, and runs 13.2's at about 100 mph. The engine makes 358 foot lbs torque at 2900 rpm.

All of that said, I don't reccommend the 7 1/4 unless you already have a good one. It is next to impossible to find a good one used, at this late date. Just as hard to find parts to repair it properly, particuly the SG unit. There are better options.