Looks to me like you just have the sill in the wrong position. Looks like the rear sill needs to move back and the whole bed moved forward.

Look at the pictures in the thread below for some decent reference pictures of how the bed goes together and the location of the rear sill. There are some bed pictures down lower on that page. (Page 2)


http://67-72chevytrucks.com/vboard/showthread.php?t=541111&page=2

The truck in that thread is not mine and I know nothing about it. It just came up when I googled a topic and I saw it had some good pictures. I haven't looked through all of the pages but it looks like a very nice truck and looks very well done.

Good luck

Last edited by 1866yellowboy; 10/22/2015 11:36 PM.