Yup, the engine has to be the same year or newer, technically. If it's an older engine that is identical to one used in a same year/newer vehicle, then it can probably be used, the refs aren't that thorough, and if it doesn't need to be inspected by a state ref, you can probably get away w/ the 87 diesel, but it technically has to be a certified engine/emissions configuration from another LDV that's the same age or newer.