Hi Tom,
Well...what we need to know is:
What else has been done to your steering system? Have your king pins been replaced? Have your wheels been aligned (toe-in/toe-out adjusted) and have your tie rod ends and drag link ends been checked for play? Has your steering box been adjusted?
Sorry for the game of 20 questions, but we need more information to get you "pointed in the right direction." Ideally you need to check everything in the steering system to be sure all is nice, tight and adjusted properly (especially your wheels) now that you have new springs. When that is done, your steering box needs to be adjusted and it needs to be set so that your pitman arm is in the exact center of travel. And at that point your steering box, drag link, tie rod should all be working together with happiness and when your drag link is reconnected, then you can adjust your steering wheel to point straight ahead. You want your worm gear and your sector gear to be exactly in the center. Here is some information from the 48-51 years...http://chevy.oldcarmanualproject.com/shop/1948_51truck/51ctsm0901.htm
