Denny,

I agree about the heat transfer being conductive in the exhaust gases setup. My exhaust set-up heats up the intake manifold faster than my old cooling system water setup. I have had no problems with the exhaust-gas setup so far. And, I have no worries about coolant leaks or hoses going bad.

The stock intake/exhaust arrangement is also conductive (very little circulation, I would think). The only different is the "flapper" in the stock set-up. Do you think that the Fenton exhaust-gas setup will be too hot after the engine warms up?

Someone (maybe Alvin?) reported that he found substantial carbon buildup in the exhaust tubes set-up (or maybe carbon buildup inside the cavity in the heater-chamber in the bottom of the manifold).