Introduced in 1975, the Ford F-150 "has been the most popular vehicle sold in the United States for nearly every year of the past three decades," according to Edmunds, the vehicle rating site. While the F-150 is also a 1/2-ton pickup, it was developed to fill the gap between the F-100 1/2-ton and the F-250 3/4-ton trucks. The 1977 F-150 was produced with several different engines; an inline 6-cylinder and five different V-8's. Determining which engine in a Ford F-150 is a simple matter of checking a decal and finding the engine code.
Locate the "Vehicle Certification Label" on the driver's door pillar. Open the driver's door and look at where the door latches, it is right above the latch post where the door shuts. On the cab, not the door.
Write down the number in the upper right of the label. It is 11 characters long and will look something like this: "F25HLDC0000."
Note the fourth character, which will be a letter. It decodes as follows: "B"-300 cubic-inch inline-six; "G"-302 cubic-inch V-8; "H"-351 cubic-inch cubic-inch V-8; "M"- 390 cubic-inch V-8; "S"-400 cubic-inch V-8; "J"- 460 cubic-inch V-8. In the above example "F25HLDC0000," The "H" is the engine code denoting a 351 cubic inch V-8.
