Manifold Heater for Cold Climates

When I first did my turbo slant six, I had a 90 degree carb adapter for a 500 Holley 2 bbl on the inlet of the turbo. At idle (in the summer) The bottom of the adapter would get ice on it, and the idle would surge. I epoxied some copper tubing to the bottom of the adapter and connected to the heater hoses. No more ice, and a smooth idle.