OK, if the online info is correct, here is a '77 base model Bonneville. The one I like for racing is the 2-door with the swept back roof line. Back in the old days we called 'em "fastback" . It appears as if the bottom of the rear window is aprox half way of the rear wheel well. This will give that extra little bit of side vision I mentioned.
The 4-door rear window doesn't go as far back, so there is less side vision. And the Landau roof has much less glass and more metal. So this type roof will give less side vision than the other 2-door roof type.
But there is a problem with these cars. There ain't many left. Most have been crushed long ago. They are not a sporty lookin car like a Bird, so there is just no demand for 'em. So, just finding one of 'em may be tuff. Therefore, I'll expand my possible choices to provide a better chance of finding a suitable car.
