Got this off the HAMB. Hope it helps with your front end problem.
-------------------------------------------------------------------------------
1. Did you properly adjust the steering box before you installed it? That is by Factory specifications and procedures?
2. New toe rod ends all around?
3. You might try bumping your caster up a bit to 5-7 degrees positive, that is the top of the axle tilts to the rear 5-7 degrees from vertical, and changing yout toe-in to 1/8".
4. This low-speed shimmy is symptomatic of bad kingpin bushings and worn front end components at the low speed and slightest bump sets it off.
"Low-speed shimmy is usually caused by under-inflation or looseness of wheels, wheel bearings, worn spindle bearings or bushings, tie rod, drag link, steering gear or spring mountings usually in conjunction with too much caster or toe-in.
Low-speed shimmy is often caused by the same conditions that cause high-speed tramp.
Either too much caster or too little caster may cause low-speed shimmy, whereas only too little caster causes high-speed tramp."
from 1936 Ford wheel alignment and service manual