Drivetrain advice for engine swap

If the 8 1/4 is from an A body I'd grab it. It's a simple bolt in deal & the price is right. To check for a Sure Grip, hold one axle to keep it from turning & spin the pinion where the driveshaft attaches. If the other axle turns, it's an open rear (or a totally shot Sure Grip). If you can't turn the two axles independantly of each other, it's a Sure Grip. There might be a tag for the gear ratio, might not.