02 3500 dually extending frame to make 84" cta

[Ironforger]

I'm a pro welder Looking to extend my 2002 3500 dually from 60" (56"actual) to 84" so I can put a 10' morgan dry cargo van body on it.Frame questions: To do this I'll need extra frame rail material which I'm hoping to rape from another salvage frame.My question is this:Are the 2500 frames the same as the 3500 frames the same material thickness, bolt holes & dimensions etc? I already know length variables exist depending on quad cab short bed etc. Just wondering about all the mounting holes for the axle, & material thickness etc. Thanks

[CUMMINSDIESELPWR]

not sure on the frame differences but are you extending the frame behind the axle or are you splitting the frame ahead of the axle and lengthening? sounds like a cool project though!

[Ironforger]

not sure on the frame differences but are you extending the frame behind the axle or are you splitting the frame ahead of the axle and lengthening? sounds like a cool project though!

Splitting the frame ahead of the axle and lengthening. CTA = Cab to Axle measurement. The 02 3500 quad cab long bed measures 56.5" actual (rounded off to 60" ) from back of the cab to the center of the axle. (CTA). Basically I'm fabricating the truck to be a cab chassis with an 84" CTA. I would die to purchase a factory cab chassis 02 3500 6 speed quad cab dually with an 84" CTA. Searched forever, could not find. But I'm lucky I found my good condition no rust 02 3500 6 speed dana 80 dually quad cab so I'm going to build my own 84" CTA. The factory cab chassis are nice in that they have straight rails but I'll make good with what I got. It would be an error to exend the frame behind the axle unless you are entering a wheelie contest lol