The Stovebolt Site Forums The Shop Area Engine Shop carb freezin-heat riser fixed, what now

I know you've all seen the tin shields on the exhaust manifolds of the 60's & 70's. The idea there was to direct warm air to the carb inlet, or snorkel tube on some of the air filters. In the 70's type Chevy v-8's there was a butterfly flap in the snorkel, that was actuated by vacuum. The warmer the engine got the more vacuum, and the butterfly opened. Ya might also check the forum and look at the post that bigmacdaddy wrote, He's got pictures too. Hope this is helpful
resto44