I'm restoring a 75 Transmode and am interested in fabricating new stronger, thicker, stiffer and more robust chassis frame rails. I'm inquiring if any dimensioned drawings exist of the GMC chassis?

I'm also designing and building a tube steel full length ladder frame to stiffen the floor beams and help to stiffen the body. This ladder frame will be resting on the rubber isolation pads. Reference drawings of the chassis would be helpful in creating my CAD designs of these pieces, ladder frame and chassis frame rails.

I'm new here and would greatly appreciate any help

Best,

Dale