[99LeCouch]

That's a neat idea! You'd let the incoming air get as hot as you wanted via scavenging the heat the engine is otherwise bleeding into the air. I think that would definitely increase efficiency if implemented.

The heater hoses are kitty-corner to the airbox in my engine bay, so it would be an octopus of coolant hose running around the engine bay. Plus finding a heat valve that was not vacuum-actuated. Not to mention getting a small-enough heater core. It'd be a challenge on this car.