[RichardJ]

>>sedan with a 235, has Fenton headers (they are drilled and tapped for heating) with just the original carb. I ran copper tubing from the headers to a plate on the bottom of the manifold right below the carb.<<

I've seen plenty of pictures of the Chevy 235 Fenton cast headers, but never with the carb heat tubes connected. In order for the hot exhaust gases to pass through the tubing, one tubing end will have to be connected to a location with lower pressure, than the feed tubing.

You could use a angled tube like used for Crankcase Evacuation Systems. You wouldn't use the one-way valve because you're connecting exhaust to exhaust.

Yes, the 292 is cold blooded and I bet you'd do better with a manual choke, rather than the electric.