I've spent 20 minutes searching the web with no luck. Doing some fab work on my pro-truck (4700) to upgrade the fuel cell to the 60 gallon versus the original 40 gallon. So not any structural work to the chassis - more tank protection/mounting than anything - but I would like to use the same wall thickness that the truck is built with. Someone must know what wall thickenss the 1.5" tube is on these trucks. I don't want to cut into a tube to see what it is...Anyhow know ?