pre 87's use the zd1a (spade connector), post 87 uses the zd9 (bullett connector)
If you are going to keep it stock make sure you test every part of the system before you install the new plugs...it is possible for the system to fail in an "on" state, in which case you will do what i did and promptly find yourself with 8 new, but well toasted plugs.
Another thought to keep in mind, the berus are NOT 12v plugs, and ford used wiring resistance to create the voltage drop necessary to keep the plugs alive....if you need to replace wire, do NOT upgrade it, use what the size/grade that was originally there. That was my second mistake...when I tested at the plugs I was only seeing 10v from the battery...installing "proper" gauge wiring brought it to full battery spec 12.2~12.4v...and promptly ate another set of plugs in 10 seconds....$200 later I decided to actually reseach this whole thing.
In some ways I like to read the manual after i have returned the product a few time for being noon-functional....the down side this time was it says on the bag 'cannot be returned after its open"...guess they knew I was comming