Welcome to the site, Dan.
The info about OKHP only ordering in '85 may be incorrect.
Does your car have an AOD? CAn you post a pic of the doortag, other buck tag, or last 6 of the VIN?
Here is a pic of an in-service unit from our website (the pic above is someone's resto).
http://www.specialservicemustang.net/Gallery/OK.htm
