For what its worth, I have an 03 Dodge 1500 sitting here we pulled the 5.7 from. With the position of the cab, crossmember, and front steering center, a late model Dodge Ram might not be a bad starting point. The steering rack goes almost straight up to the cab from the rack mounting point on the front of the crossmember, which should be about right for an older COE.

This truck is the first "late model" Ive been up close and personal with. I can tell you that 1500 is more heavy duty looking then any of the old 1 ton 70s & 80 trucks were. You could easily loose 18" of frame rails in front of the crossmember and suspension mounting points without loosing anything important. It might be worth checking some measurements on 2003 to 2008 trucks, they are pretty easy to find with dead 4.7s and rusty cabs/boxes and can be bought pretty cheap. Gene