The only difference between the second cross-sill on my truck (also from Mar-K) is the "bedside brackets" on the end. Mine is just straight with no brackets and is the one that floats above the frame just in front of the frame hump. The only one that has anything additional near the ends is the rear cross-sill. I think you could use it, but the brackets could be removed. I don't see how thy could attach to the bedsides, but I could be wrong. The third cross sill has bolts thru the wood and frame. The front cross sill has holes along the front edge to bolt to the front panel of the bed. Here's a picture of the 4 cross-sills when I first primered them after getting them home from Mar-K. And another with the front and rear cross sills bolted to the bed sides. You can see the extra bracket on the end of the rear sill in that photo.
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IMG_2270.JPG (255.46 KB, 97 downloads)
Tailgate and cross sills from Mar-K getting primered.
IMG_6024.JPG (267.16 KB, 92 downloads)
Bed assembled with front and rear cross sills. The 2nd one from the cab only bolts to the wood and angle strips.

Last edited by klhansen; 07/09/2026 1:59 AM.

Kevin
1951 Chevy 3100 work truck
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1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car)
Busting rust since the mid-60's
If you're smart enough to take it apart, you darn well better be smart enough to put it back together.