Dean's Car

Dean's trademark black 1967 Chevrolet Impala was passed down to him by
his father, who bought it in 1973 after Dean, sent back in time by Castiel,
convinced him to purchase it over a 1964 VW Van in the episode "In
the Beginning". It bears a Sedgwick County, Kansas license (though
their hometown of Lawrence, Kansas is actually in Douglas County) plate
KAZ 2Y5, a reference to Kansas, the Winchesters' home state, and 2005,
the year the show premiered. Starting in the episode 2.20 "What Is
and What Should Never Be", the car sports a new Ohio license plate
(CNK 80Q3) to aid the brothers in hiding from the FBI.
The car has been prominently featured on the series, beginning with the
teaser of the pilot which shows John Winchester holding his two sons as
he sits on the car and watches his house burn. The car is Dean's most
prized possession, and he protects it with nearly the same ferocity with
which he protects his family. Despite this, however, he attacks the car's
rear with a crowbar after a talk with Sam in the episode "Everybody
Loves A Clown" due to the pressure from his dying father's secret
about Sam. In the pilot episode, the trunk is revealed to hold various
weaponry to fight the supernatural.
In an interview at a convention, Ackles said the main Impala they use
has a 427 and skid plates. The actual car was bought from the Kelley family
of Farmingdale, NJ in 2005. The Kelleys were the second owners of the
car, they bought it from the original owners. The car was bought new in
1967 at Mathews Chevrolet in Farmingdale, NJ. It was originally baby blue
with baby blue interior and dual bench seats. After Sam inherits the car
following Dean's death in the third season finale, he revamps the radio
with an iPod jack.
Source: wikipedia.org