Factory had different length fan clutchs. For example, a v6 fan had a very long threaded portion. The 92-93 magnums had a mid sized one. The 94-03s varied a little based on HD cooling or not, or at least thats been my obervation with my junkyard engines. My 92 w250 had a spacer washer behind the fan clutch as well to get an extra 3/16 inch forward. Only seen them on 92-93s though, and not all of them. Very thick metal washer - not a hardware store piece without alot of milling.