man great find, i love those 49's. They kind of look like airplanes to me.
A couple months back there was an artical in old school rodz or rod and kulture that made a 4door 50 or 51 into a 2door, by getting 2 additonal doors, to strecth the original doors then moved the door latch pillar and part of the window back(dont know what that peice is called..."B" pillar maybe???)
i could try to find it if you are interested??