1. make sure is VIN R engine. VIN U and others won't work.
2. even then will have to reuse some 84 parts and wiring.
84 cars may have engine replace under Warranty/Recall work.
So your "84" engine can be really 85-86 engine.
See my Cave, Duke Quick Ref
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
The Ogre's Fiero Cave