Wheel base size ?
 

does someone knows what the wheelbase size is from the Haynes chassis according the book ?
Wheelcenter front to wheelcenter rear ?

On my CAD 3D chassis, I found 2,931m.

That does not sound right. On my roadster it's around 2380 mm, down from 2608 mm on Sierra.

The design wheelbase is not so trivial to work without a CAD model out due to the caster angle and upright trail offset on the front axle.

I had to go to the garage to check. And you are totally right Alga.

So why the measurements on my CAD drawing are wrong? They are not, but I am, I made a typo: I swapped the 3 and the 9: it is 2.391m and not 2.931m :D

Sorry about that :o