Hi,
I have power steering on my M37, if you are having wobble your knuckle bushing/bearings are bad providing you used the original idler arm assembly and kept the original lower steering arm. I have owned many of these trucks and I can tell you if you have steering wobble it is your knuckle bearings causing it. I don't think the "stabilizer" will help much, I do run a "stabilizer" for bump steer prevention but it will not cure the wobbles, Jack up your front, pull the wheels and pop the tie rod ends, steering arm loose and see if your knuckle moves freely back-n-forth, if it does there is your problem. The knuckle should have 20 pounds of drag if your bearing/bushings are good, you should have to really work to move the knuckle back-n-forth> when I pick up one of these gems I always rebuild the knuckles to pevent steering issues as you discribe, I once had a close call to know how important good steering needs to be.
Good luck, Eric..