Anyone use a S10 Bed floor in the 55-59 shortbed trucks?

[OKGMC4]

Mine is out of an 89-96 Dakota. The yard I went to had a ton of S10 and Ranger short beds but no long beds, and the short version is too short. The Dakota bed is 78 3/8 long and I need 77 3/8, I just cut the extra inch off the front end. That put the center of the wheel well around 37", exactly where it needs to be on a TF truck. The measurements for the TF I came up with are 77 3/8 long by 50 1/8 wide. The Dakota looks just like the S10 from the bottom. I may still end up using the stock rails as mounts but I 'll have to modify them to accept bolts from the bottom so all fasteners are hidden. It's just that the Dakota is a bigger truck and actually closer in size to a TF. I suspect the AD truck beds are smaller.