Part Question Regarding Rocker Panels

No, what goes down there is a special nut. The fender bolts directly to the rocker panel.

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You need to "fit" the gap with body shims. Not enough shims, and the bolt will draw the fender up and make t bow outward, conversely, you can put in too many and it will pul the fender down and in. If it lines up good ith the dor then you simply shim the gap to cover the distance and tighten the bolt down.

Look up in the hole under the rocker, is the hole square and in good shape? If its rusted it won't hold the clip-nut tightly. If it's bent up, you will need to straighten it out. THis clip-nut thing, if you have not seen on installed on a car correctly, can be tricky to understand how it sits in there. The two wings sticking out will be visable to you when looking up at the hole. And should be oriented to the inboard (towards the center of the car). It will go up inboard, then slid outbord to snap in place. If it is too loose, you can bend the wings up slightly to make it a bit tighter. Emphsis on "slightly" as they will break easily.