Hello there...
Here's the link to the digital photo collection at the NAC
http://www.archives.ca/02/02011502_e.htm
Just enter your topic (truck or Ford or General Motors), tic the 'digital' box and you're in.
David, Clive is right.
You've really got to buzz over, settle in and plow through the archives.
It's a little like the internet, though. There is so much interesting stuff available you have to guard against getting sidetracked.
Steve