Next I take off the distributor cap and coil to gain access to the plastic left hot air duct. There are four screws to remove. Two up top, one into the left side of the fan housing, and one hidden down below just above the chain cover.
Here's the bottom one:
We pulled the duct out from the back. The back side is pretty well clogged up with plug wires. Arrow shows bottom bolt.
Duct removed.
That finishes up the removal of all the stock heater components. There are a few different ways of handling the actual backdating of the heater ducts and hoses. The earlier rear most tin did not have a built-in duct at the left corner, like the stock SC tin. A is the SC rear tin, and you can see the built-in duct to the left of the A. B is the side tin piece that joins A to C that runs along the left side of the engine and attached to the cam housing.
Here's a picture of an earlier rear tin "E" with no duct. On the earlier cars tin "F" had a hole and was used to route the heater hose from the left hot air duct down to the heat exchanger.
The right side engine tins are the same on the SC as the earlier cars, at least for the purpose of backdating. In other words, the short tin that joins the rear tin and the right side tin has a hole in it for the hose. Below is the right side tin from the '83 SC.
A couple approaches here work. First, the hose from the left hot air duct can be routed directly to the stock SC tin and its built-in duct. That looks like this:
Versus routing the hose to the earlier small tin, which looks like this:
The advantage of using the SC tin is, you don't have to replace the tin. Just leave it in place. You also don't have to find/buy the short tin with the hole in it. The advantage of using the short tin with hole is a straighter shot for the hose from the hot air duct to the tin and down to the heat exchanger. It's a cleaner look, and might give a little better hot air flow to the cabin, but I'd bet that's splitting hairs. Here's what the hose routing looks like from the side using the stock SC tin. Yes, this is a 3.2 Carrera engine and SSI heat exchangers, but the results are just about the same.
