The Prototype
This car has a wheelbase of 118 inches, and an overall length of 206 inches. It had a 110hp V8 engine and manual transmission. Over 120,000 of these two-door cars were sold.
(source: PBase.com web site)
The Model
Release 5 of M2's Auto-thentics has two models in it that fit my 1950 layout. This model is of a 1949 two-door Mercury sedan. The doors and hood open. The only issue I found with them is that some of the rubber tires were not on the wheels straight, and they were a bit difficult to get right. The vehicle's overall dimensions are just about spot-on (length is of by one or two scale inches). All-in-all the model appears to be very accurate. I have bought three different colors of this car.
FYI: I have also bought a Racing Champions model of car, but it is scaled to 1:60, and so is quite a bit larger than the model shown below. It comes out to being about 15 scale inches too long.