ABR,
I'm not sure that's the route to take. The stock shocks on 2500's are crap, first of all. Also, I'm confident they are valved completely differently, just to support the weight of the 2500's front end.
You might be better off searching a wrecking yard for a 1500 with aftermarket shocks on it. I'd certainly go that direction before takin stock shocks off of a 2500 to install on a 1500. Even if you are only going a few turns on the torsion bars, I'm not sure you'll need a shock of the 2500's length, but I'm sure someone that has done the torsion crank on a 1500 will chime in here soon.