The previous owner fabricated an air dam out of sheet metal. I wanted something better. I bought the three piece air dam from eBay. It was easy to see where the big center piece attached to the lower radiator support. Once that was done, I had to figure out where the smaller pieces were attached. I finally figured out that they are attached to the rear of the bottom front ground effect on each side. They extend from the center piece toward each tire. That would be easy, but of course, the mounting tabs on the ground effects were broken off. I decided to drill 5 holes in the side pieces with matching holes in the ground effects. I attached the side pieces to the ground effects with zip ties. Each side was lifted an inch or two and attached to a cross brace with zip ties. The side pieces seem strong enough to support the ground effect pieces and give structure to the plastic. It can't be seen unless you are under the car. We'll see how it holds up after a few thousand miles. The photo is looking at the left side from the back of the side piece.

 

http://www.hawksthirdgenparts.com/pr...Deflector.html
Your 85 TA should use the one piece air deflector,not the 3 piece.Is their a reason you went with the 3 piece.??

 

My understanding is that the 3 piece is larger and will cause better air flow through the radiator.

 

If the center support for the one piece style was missing, then its easier to replace with the three piece style as the center piece combines with the support.
The three piece style does not cool any better, it s more resistant to breakage from curbs. The years with the three piece style cool better because they also added ducting above the scoop and in front of the scoop on ground effects cars.