You can wrap copper tubing around a header tube and the intake with both ends open, the heat will flow up the tube and around the intake. Not the best way but it will work. You can also heat the air using a newer air filter housing and stove pipe tubing, still better then nothing but useful. Even in 75* weather, a hot intake is needed to keep the fuel vaporized. I had a triple carb intake for awhile with no heat, it took forever to run decent, and even then it wasn't all the great.
