How To Create Blueprints

 Could not find blueprint for 1957 Hillman, so I used method John Nitrous taught me to trace over pictures of real thing. Basically, you use multiple pictures to remove all the perspective errors from reference pictures. For example dark blue Hillman on bicture below has very badly warped vertical door seams. But it is only one of the pictures that is taken low enough to show silhouette of rocker panel and could be used to move things on right place on vertical axis. Red one on bottom right has very straight shot of side window. Green one shows that back edge of bonnet should be straight.  I did not have too many samples to test blueprint against, so it is not absolutely correct, but it is good enough for my purposes. You can do even better.