On a correctly setup steering, you can run without a steering stabilizer without any issues. It can be a number of issues. You mentioned that it looked like your lift was mostly a shackle lift? What are the length of your shackles? If they're outrageously long, that can and will cause steering problems. Pitman arm tight? Are the shackles too loose? Are your wheel hub bearings in good condition? Ball joints? Joints on your steering shaft? Alignment?
Front end issues are one of the hardest things to diagnose, but all the above mentioned (plus some I'm sure I've forgotten to say) should be checked when trying to figure out steering problems.