Hey shaun, this may sound crazy but how about contacting someone dealing with the actual racing?
When I research color schemes, stripes, decals, etc... I sometimes
collect info from forums, car dealers, sponsors (maybe Marlboro
directly), race historians, etc...
Sometimes an email explaining what you are doing and why you need the
info, sparks a quick reply. You'd be surprised how many people are
willing to help someone out that is trying to create a small scale
replica of their car. There are times that I don't even get a reply
though.
Just a thought...
Good luck in your search.