cross sills with a c notched rearend

[Hilljack51]

I found a similar thread from the forum, and even though he's raising a steel floor it should be able to give you a pretty good idea as where to start.

http://www.67-72chevytrucks.com/vboa...d.php?t=443970

I really think that keeping the flat floor in the AD trucks by raising the floor to clear the tires and chassis takes projects to the next level.