Gonna get rustys 3"aal what spring rate

What spring rate should i get 150 or 180 i dont really tow anything or carry alot of heavy junk in the back ive already got a cut up ford leaf spring in place of the helper just to have the existing pack keep there shape.

180 will ride harsher if you don't carry extra weight. Go 150 unless you plan on adding more weight in the near future. You'll have a smoother ride.