The Mantis

[6 Door King]

Bought a 1967 C-10 a couple months ago for 1400 dollars and a shotgun to boot. Brought it home, drained the gas tank, repainted it and fired it off. Replaced most of the little stuff so far, and added a set of 94-96 Impala SS wheels. Has a stock 350 with Holley 1850 and Edelbrock Performer RPM manifold. Added a trans cooler for the TH350, and against my better judgement a chrome dress up kit for the engine.

The current plan for my new rig is to stretch it to a crew cab, and add a tilting flatbed to it. I have a dual axle car trailer that will be sacrificed as well as a 69 long bed frame, along with a 78 longbed frame. While this will be a build thread, it will also be a "what should I do" thread with opinions truely valued, and previous experiences prefered.

Really need opinions on how to best accomplish my frame work, and whether to box or plate the frame, or run all new tube or channel? I have access to almost any type of tube or c-channel as I used to work in a fab shop.
I plan to run a 14 bolt rear with a tag axle from my car trailer to supplement the weight capacity. My thinking is since my car trailer has a realitively light tongue weight when loaded properly, the load transfered to the front axle should be negligable. Already have the big disks in front, and want to keep the 5 lug front (again, the rears will carry the load). Anyone want to chime in on whether it would be better to have the drive axle (14 bolt dually) in the center axle position or at the rear axle position? I have heard horror stories of guys getting one axle off the ground and going nowhere due to drive wheels not contacting the pavement. I do not plan to offroad it, but I also want to ensure I always have drivewheel traction.

I think I have a solid plan to stretch the cab, and body work is my specialty, so this area SHOULD be the most comfortable part. I will try to take alot of pictures as I go.
Here's what I got to work with so far (please ignore all the junk in the bed), and the trailer I mentioned is under the truck...