I run that set up with the water running through the plenum area. Problem is it takes about 8 - 10 minutes in cold weather to warm up the intake and warm up the air/fuel mixture. No choke and an open style air filter.

One interesting thing is my water is warm in about half that time, but it's not bog free until way later.

It's 100% most definately the cold intake. I have a capilary style coolant heater. Since it's plumbed up through that plenum passage. I can make it very warm yet the engine itself is still cold. With that situation, the truck drives totally bog free even though the rest of it is cold.