The first is a ram-car, inspired by some made by the game's author, Carmen Cerra. It's based on a 1957 Chevrolet from Matchbox:
|The Pointy End|
The other car is apparently a 1964 Buick Riviera from Hot Wheels. It has a couple of machine-guns, and plenty of armour plate:
It was originally a lurid, sparkly purple. I painted it grey pretty much as a neutral undercoat, but actually liked how it looked, and eventually went with a Confederate ironclad theme.
As I write this, two more vehicles are in the workshop (as it were).