The 65 galaxies had two tubes going to the pass side exhaust manifold to get heat for the choke,there is some vacumn that comes from the choke thermostat housing that sucks the heat from the manifold. One tube bolts to the choke thermostat housing and goes into the manifold and the other comes from the manifold to the top of the carb,the heat air is drawn from the top of the carb down through the manifold and into the choke thermostat. I have a exhaust manifold from a 65 289 that still has the two tubes and could possibly have a manifold from a 352/390 that still might have the tubes. Jeff