I think you're asking something that didn't exist back in 83. A quad suspension refers to a suspension system that is independent in all four corners, meaning all the axles are able to flex and move. GM does not make anything like this in trucks as they always have the rear axle as a solid member except for some newer ones for the quadrasteer. Back in 83, the front diff was a solid piece with some U-joints at the steering points. These could be considered independent suspension, but if you drive in one you know that was not the case.
