Since it's going to be a street/strip vehicle I suggest going with some sort of limited slip or locker differential. However you could still run a spool on the street if desired.
Some good differentials to choose from would be a FRPP 31 spline Cobra unit with the carbon clutch pack, a Torsen T2R, or a Detroit Locker. I've got the 31 spline Cobra unit with an extra clutch and shim on each side. I also have the absolute minimum amount of friction modifier in the diff fluid.
Next up you'll need to decide on axles.
I recommend going with stronger 31 spline axles from Strange or Moser.
While ordering axles you'll want to decide between keeping the C-clips, going with C-clip eliminators, or welding on Ford 9" axle housing ends.
It's best for safety (and required in some drag classes) to get rid of the C-clips.
The easiest way to do this is by using the C-clip eliminators. But the 9" ends are the absolute best. But requires cutting and welding.
Now you need to decide on what rear gear ratio your going to use. This will vary depending on many different factors. But a good choice would be either 3.73:1 or 4.10:1 ratio.
This is a good start; and what most do. But from here you can do several other things.
You can (recommended) weld the axles tubes to the center housing.
Also recommended is a differential girdle.
Then there are diagonal braces that can be welded to stiffen the housing.
