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One of our lads is into these trucks too also we're in the same rust predicament here in Ontario Canada although blessed w/ General Motors plants being nearby so an abundance of used GM product around.
Is there a reason you don't want the '08 and up trucks as some go as cheap as the earlier ones now also amazing what deals pop up if you're tuned to recognize them and act quickly.
Best look for original non-repaired body trucks someone's rust proofed w/ oil type products also consider the newest high-miler deals you can afford.
Good luck also great how you're doing this w/ your boy!
~ Pete
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