In
some domestic vehicles, there are two or more engines that are
the same size but do not use the same parts. In order to
properly identify the correct part(s) for your vehicle, you
must first match the engine code from your Vehicle
Identification
Number
with the character shown next to the engine type on our
Vehicle Search Results page. You can find your vehicle
identification number (VIN)
on the vin plate:

If your vehicle
is a Chrysler, Ford or GM product manufactured from 1972-80,
use the fifth character on the VIN Plate, or if it was
manufactured from 1981-98 use the eighth character.
If your vehicle
is manufactured by AMC/Eagle (except Jeep) from 1974-80, use
the seventh character, 1981-88 uses the fifth character and
1989-98 uses the eighth character.
If your vehicle
was manufactured by Jeep from 1972-74 (up to Serial Number
100000), use the eighth character, 1974-80 uses the seventh
character, 1981-88 uses the fourth character and 1989-98 uses
the eighth Character.