Possibly the most famous Mopar engine line of all, The Chrysler Corporation's Hemi engines were only used in Chrysler, Dodge and DeSoto vehicles, with the exception of those used for marine applications. Identifying a true Hemi block requires retrieving the engine stamping, date code and casting numbers and then cross-referencing them with a Hemi code listing. As Hemis are highly sought-after, checking these numbers is necessary for proper identification. According to Hot Hemi Heads and The Hemi.com, there were 13 different Hemi engines of varying displacements during the Hemi-heyday, between 1951 and 1971.
Locate the engine block casting number or set of casting numbers on the side of the block. According to Year One, the casting numbers are easy to read and are unique to the engine displacement size. Chrysler Corp. engines do not share casting numbers with those of different displacement. These numbers are not always in the same location, and are normally seven-digits long, but may be longer. Year One has a partial listing of these casting numbers.
Locate the engine stamping on the V-8 ID Boss. According to Year One, the number is located in front of the intake manifold valley pan towards the driver's side, next to the distributor base. This number is the most important in identifying a Hemi. Since the information is hand-stamped, it may be hard to read.
Decode the stamping number against a listing similar to those found on Hot Hemi Heads and The Hemi.com. The number will identify the displacement, build date and other important information concerning the engine.
Locate the date code on the side of the engine block. This code is not in a set location. The date code gives the exact date of manufacture and may be compared to other castings to verify authenticity. The date is in an easy-to-read format, such as 3.23.68.
Gathering and comparing all three sets of codes offers the best way to assure accurate block identification.