While the steering stabilizers certainly help, replacing or upgrading (from none to a single or from a single to a double or triple) is not a substitute for repairing worn out front end components.
As BroncoJoe said, the tie rods, idler arm, steering box/pitman arm, ball joints & track rod are the places to start. The stabilizer(s) help dampen sudden steering movements (particularly off-road) but the core of the problem will be elsewhere. I'd start by looking at the tie rods & idler arm, then ball joints & finally steering box (in order of expense & hassle
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[email protected] 2x" width="20" height="20" /> ). Your truck doesn't have a track rod so you can skip that one but also take a look at the condition of all your front end bushings as they contribute as well. The steering shaft connector can also be a source of play as well but they aren't nearly as bad as the old rag-joint connectors the 78/79's use.
The pitman arm isn't generally a wear & tear item. It bolts onto the splined output shaft of the steering box so if there IS a problem with it the steering box output shaft splines are probably damaged as well & since that's a hardened part the only fix is a rebuilt box & new pitman arm.
You didn't mention if the truck was lifted or not but with any suspension lift over 2" you should really be using a dropped pitman arm as well as having all of the necessary drop brackets for the axle pivot points & radius arms. A lift comprised of nothing but larger springs will cause the truck to wander around with very vague steering.
It's helpful to add the basic info about your truck (year, engine, tranny, lift & tires) to your signature so everyone knows what you're working with without you having to remember to add it into every post
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