this is my 66 convertible. they had seat belts in the rear.
the darker section is a 72 dart floorpan modified in the front seat area to use 97 sebring seats front and rear but the spotwelds are the same as the original 66's welds. car is on a rotisserie and flipped on it's side to view the undersidein pic #1
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ignore the second arrow pointing to the rear there is only 1 hole in side of the rocker panel that is threaded.
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this is the top view of picture number 1
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hope this helps.
