143 tooth neutral balanced flywheels.

http://www.rockauto.com/en/catalog/dodge,1992,d250+pickup,5.2l+v8,1086140,transmission-manual,flywheel,5348?a=Referer+www.bing.com+URL+%2F

There are also billet flywheels from places like 440Source for not too much more, and a billet flywheel is safer.

The flywheel will be drilled for an 11" pressure plate, either diaphragm or Borg & Beck, they use the same bolt pattern. This bolt pattern will also fit a 12" pressure plate.

Good news for you is that the 11" pressure plate will work with a 10.5" disk, there'll just be around 1/4" of pressure plate that doesn't get used.

OR, you could have a machine shop drill the flywheel for the 10.5" pressure plate. I did something like this and it cost $35.00 Holes are drilled all the way through and threaded, then counterbored so no threads pull up and keep the pressure plate from seating.

R.