start with the obvious.
Did you use a sas kit, if not you may have a caster issue.
break out the tape measure check rough alignment, and square of front axle to rear axle
put the back tires on the front, see if you got a poorly balanced tires,
tightness of shackles and bolts.
Toe out helps but to me it is tiring to drive that way cuz you are constantly correcting.
