More Heat From Stock PA12 Exhaust

An old trick Atlee used to tell us was to simply take copper or stainless "Brillo Pads" and pull them out so they will fit into the space between the outside of muffler and inside of the shroud. That will create considerable more potential heat than just rushing cold air over the hot muffler. However that reduces flow, so on some systems you need to run another hose from another inlet source to bring flow back up. It definitely creates more heat but can't speak to legalitys nowadays likely
something the gov wouldn't want you to do. Likely a $3000 exhaust would be the legal path vs $3 worth of stainless wire?

PerryB said:

Stewart, the left side of that system is carb heat. There is a baffle around the middle of the muffler and that heat shroud assy. is effectively split into two separate systems. The cabin heat supply is from the right front baffle, post#3/pic.#2.

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Is this actually the case and therefore do both halves of the heat shroud need ram air? I'm guessing one ram air source is from the top rear baffle (on the right side in my PA-12) and the other is from one of the 2 lower cowling intakes? Does it matter which ram air source powers the carb heat and cabin air sides?