This is done with the hinge position. On occasion, it may be necessary to enlarge the holes in the body thereby allowing more room to move the hinge.Are the left and right corners adjustable as far raising or lowering along the firewall? Mine on the passenger sides is higher than the drivers side.
Joe, the hoods and associated parts are different just enough that the article is not a ton of help for 39 - 40.In the 2009 May/June issue of the V-8 Times there was an article on adjusting 1941/1948 hoods. It has photos. I am not sure if this would relate to a '39 but it might shed some light on the job.