The right side of the engine is a bit easier, especially if you're not running A/C. But again we've got both here, so that's what I'll show. On the '83 I bought hot air duct # 911.106.327.00. I'd read that these don't really work on cars with the A/C bracket, but I was pleasantly surprised when my bracket fit really nicely over the duct.
Here's the opening without any duct.
Here's the duct in place. It attaches with three screws. The two on top of the fiberglass shroud...
and one underneath that screws into the chain housing. You can see the duct doesn't fit perfectly against the top of the chain housing (cylinder fins are peeking through.) This can be tweaked with some manipulation.
And here's the installation on the '79.
We ended up using some of the hose that we removed to route to the heat exchangers. Arrows point to the fasteners, plus the one below (shown above on the '83)
The hose on the right side is one piece, and goes from the hot air duct, through the short tin with the hole, terminating at the heat exchanger below.
And here's some pics of the right side duct under the A/C bracket on the '83. I don't have pics of that engine in the car yet, since it's still in my woodworking shop, but I think you get the gist, it will look nearly identical to the '79 when complete.
One thing I haven't figured out yet and that's how to disable the electrics for the blower motor that gets removed. I do recommend taping off that lead from the engine harness, but I'd also like to disable the call for power to that lead when lifting the heater levers inside the cabin. If anyone would like to complete this thread with that info, that'd be great.
So that's it. I hope this info is helpful and that I haven't shared a bunch of bad instruction here. Like I said before, I'm pretty new to all this, just sharing my experience.