I found an old UPC 1/16 Ford GT40 kit on E-bay a while back.  Just dug it out of the box about a week ago, what a disappointment.  It is more toy than model.  Decided to measure it up and give it a shot anyway.  The first and most glaring error was how flat sided it was when viewed from the top.  The rear deck has to be widened by 8 scale inches over the centerline of the rear wheels.  The front/nose has to be widened by 5 scale inches.  I tackled the rear deck first and this is the outcome (still in primer). 
 
 
As you can see it is really flat sided. 
 
 
Now I have to tackle the front end. 
 
I would like to hear from anyone who may have previously built this model and see your final results.