Jimmi,
The intake manifold needs to be heated (due to latent heat of evaporation - cooling that takes place when the fuel is vaporized).
When I learned that the intake has to be heated, I went with the coolant/plumbing solution aand it worked fine.
When I changed engines a few years ago, I decided to go with the simpler exhaust gas method, using two pipes from the holes in the Fenton exhaust manifolds to Jim Carter's plate. This works fine and probably heats it faster than using the coolant (and there is no need to fret about water leaks).
