I've done many. You'll want to make it a 60" CA unless it's a dump and then it is 72" CA. I assume your talking about just running the inside dual on the rear? I'm sure that is all the DUCKs did as it was a standard 6x6 GMC chassis.
You do not say what type of body you want but every body company I know of (and thats nearly all of them) makes every size of platform, van, dump, tank, etc. Offer your location and I may know someone or be able to recommend a supplier.
If you are unsure how to modify the frame send me a private e-mail and I'll walk you through it.
Last edited by 53moneypit; 04/24/2008 6:46 PM.
