On my 1 ton I did what Kevin suggested and splice things together. However, mine are not originals and do not have the ribbed top. They are flat all across the top. I got one large piece of sheet bent to the bends I needed. I then had to cut them and then reweld them together to get the taper I needed both front and rear for the dually. It was a pile of work. The single wide running boards were easier to fab up.
I have an old build thread here:

https://www.stovebolt.com/ubbthread...ad/Board/45/main/163250/type/thread.html

Hopefully the old phtotbucket links work. Grrr.

Last edited by Fox; 03/24/2020 2:08 AM.

1970 Chevrolet C10
Grandpa's -- My first truck -- In progress to shiny
Follow the build in the Project Journal
1950 Chevrolet 1-Ton Dually
"Ole Red Girl"
In the Stovebolt Gallery
More pictures here
1951 GMC 9430 1 ton dually--Shiny! | 1972 Chevrolet C20- Rusty- the puzzle box lid for the C10 | 1962 AMC Rambler American- my wife's
Parts trucks-
1951 GMC 9300 | 1951-GMC 9430 | 1951- Chevrolet 1300