I opted to keep the SC tin on both the '79 and the '83 because it meant less work, less hassle, less money.
Now lets talk about what hot air ducts to buy. For the left, I bought part # 901.106.321.02. This is the stock left hot air duct for the earlier cars. When fitting this duct to an SC, the distributor, and more precisely, the distributor cap and wires may end up too close to the duct. I had to heat up the duct to make it more pliable and "massage" as they say the metal with hammers and various implements to get everything to fit. It took me a while, but I eventually got it to fit and look pretty good. Here's some pics of that process.
Here I'm test fitting the duct against the plug wire. It's just barely kissing the sheet metal.
Here's what the duct looks like on the front side. I tried to shape the metal so it conformed closely to the shape of the surrounding parts.
Once I was happy with the fit I painted the duct then screwed the duct in place. There's a screw on the underside that's easy to forget.
The upper front screw also holds the adele clamp for the wiring harness.
The other screw that attaches to the fan housing had a rather large hole. I didn't fill this, but maybe I should have?
In order to avoid the hassle of fitting this early duct to the SC distributor, the duct from a later Turbo 911 can be used. Part # is 930.106.321.02. This part however is quite expensive, and costs about $100 more than what I paid for BOTH parts listed above. I felt an hour with the hammer and some engine paint was work the cost savings. The turbo duct has a deeper concavity where it meets the distributor cap, so there are no clearance issues.
On the '79 we used the same early duct, hammered away, and got it fit and installed. The original hose was still connected to the rear tin, so we simply started cutting it back until it would slip over the hot air duct.
This hose does not like to cooperate! I can see why some folks are using the orange aircraft hose. That stuff looks a lot more manageable. But we got it eventually.
The duct comes with two tapped holes on top. These aren't used on the SC that I can tell, so we plugged them with two tin screws. Underneath the car there are no changes to be made. The hose from the stock setup can remain since its not connected to the upper section of hose. It's a separate piece.
