Here they come!

51=Cool piece! Thanks for sharing
9 grille bars means 1950, but convertible could be either Super 56-C or Roadmaster 76-C,
Super 56-C (bumper extensions were optional accessories):

Roadmaster 76-C:

without portholes or side trim, it's up to you to decide! (4 times as many Super convert's were sold than the Roadmaster ones)

61 =I think is the coolest Buick you've got. The body style is called a Sedanette. Depending on the portholes, it could be anything, but I bet it is a 48 or 49.

52 = 52 Buick Super Riviera 2d ht model 56R (side trim does not continue behind rear wheel opening)

53 = Ford C-Series

55= 39 Chevrolet Master Deluxe Sport Sedan

bumper matches, and the 36 Ford has a one-piece windscreen

56=53 Chevrolet Sedan Delivery (The 54 grille is wider and wraps below both headlamps)


http://www.cadvision.com/blanchas/54pontiac/pix.html

57 "Passion" should be based on a 51 Mercury 2d coupe (I don't know if they were all sold as Monterey)

32=Autocar or some defunct brand?
34=IVECO/SCANIA?

I composed this on MS notepad to save time and some pain .