Determine which engine your 1980 - 86 Ford truck came with. However, note that the 1980 engine code is the 4th digit of the VIN, and 1981 and later engine codes are the 8th digit of the VIN. Find your engine code from your VIN and look it up in the table below.
The character in the VIN that indicates the engine changed from 1980 to 1981, as described here:
And here are the characters and what engine they represent: