Not wanting to start an arguement but I've been running Tom L's H/W and a pair of C/W's on my Offy intake using the exhaust manifold heat. After 4500 flawless miles, without so much as a hiccup out of my "tweaked" 235, I see no reason why it wouldn't be a viable alternative. If the Offy manifold was designed to run with only water heat, why would the sprue and riser holes not have been sealed before being sold? Secondly, the plumbing of engine coolant just leaves you open for potential leaks that could leave you sitting beside the road with a cooked engine. Of course, the choice is yours....but I have tried the "forbidden" exhaust heat and have verified (with an infrared thermometer)that it DOES work, is much simpler to install and provides instantaneous intake heat, and IMHO should be considered as an option.
Dave
