Help needed from the Ducktail Detectives

[mobius911]

My ducktail is a bit of an oddity (yes, an odd duck). I've never seen one like it, or at least I've never seen one that was original that looked like it- mine has a straight brace that goes all the way from latch to grill. Furthermore, the date of manufacture of my car, May 1973, would indicate that the tail should have a steel frame, and it didn't pass the magnet test. So I resigned myself to having a repro all-glass tail that I would replace with an original at some point.

But one thing that kept nagging me was that there was a functional reason that the car had a straight brace- it came with factory AC (one of 50 RS's so equipped), and the long brace was needed to provide a mounting point for the center U-bracket for the AC condensor. So finally this weekend I scraped off a bit of paint on the frame, and to my surprise it's aluminum. The frame also has the drain holes in the corners and the holes for the rubber tie downs. There are no weld spots on the edge of the frame (in another thread Chuck Miller mentioned this as a "tell" for frames made from production lids). The brace is attached at the latch end by 4 rivets.

So here's my theory. The factory made an initial run of ducktails with the straight brace for cars that would be equipped with AC. That run was done early in the year so they all had aluminum frames, and they were just used as needed. My build came up while there was still some stock from that initial build.

Have any of you seen an AC-equipped RS or have any documentation, and if so do those tails have the straight brace? Any other theories that make sense of this?

[mobius911]

While looking at the pictures just now I noticed an extra buildup of fiberglass inside tail just above the latch area- it's most visible in the bottom photo. On closer inspection it looks like either the ducktail had the standard curved brace at some point, or they were made with extra fiberglass there to support the brace once installed. It's possible the original brace came loose and it was replaced with the straight brace, or the factory did it that way.

[fryardds]

Hi Jeff,

You have answered your own question. I have seen a couple photos of Carreras with A/C and they had curved braces. The A/C part that was mounted under the grille was the death sentence for your curved AL brace. So the owner at the time had this standard lid straight brace put on with rivets.

A good friend also had a third series RS not far from your VIN and he too had an original AL frame tail on his car. So the Factory was still putting these on after the homologation process was completed.

[mobius911]

Thanks Brian, that makes sense. I wasn't sure a standard Al frame would have still been available this late, but as we keep discovering, there are no absolutes with respect to cutoff dates and which cars got which pieces.

And given that this brace has worked for me for 28 years, I'm inclined to leave it as is for now.