There are several companies that have them....but the one I reccomend is www.protorque.com. 1-631-218-8700
Ask for Joe Jr. and tell him Mark from Dr. Nick's in Milford sent you.
I've had one of his converters in mine for over 2 years. I plow, race, tow with it and have had no problems.
You can also order one from GM for a Trailblazer.
Good luck