The system you are talking about is usually referred to as the pre-heater. It's a shroud on the left-side exhaust manifold and a tube up to the the fitting on the bottom of the air cleaner snorkel. This fitting sits below a vacuum-actuated, thermally controlled valve. It's basically the standard set-up.
The original aircleaner is a single snorkel with a chrome lid. (I believe.) Daniel Dykstra has done ALL the research on this.
