[wrightz28]

IT's not really a HP gain, more or less I call it a maintained level. With mine before I ran the bypass, when the motor was up to temp, the power would fall off due to the hotter air coming in. Now, with the bypass it's nowhere near as bad and pretty well contant.

As to how much a little area of hot coolant can effect things, I'll say this much, before doing it, try touching your intake manifold after running at operating temp. Little hot huh? With the bypass, it's nowhere near as hot and you can actually touch the intake, thus IMO cutting the upper engine temps and possibly adding some extra life to the distributer components and other sytems.

Draw backs, yes not a good idea to do in extreme cold, although the icing thing I don't really see, throttle blades did ok on carbs without freezing for years. And at idle things do seem to heat up a little quick, however nothing a adjustable fan switch can't fix, which should also be in your list of "cheap" mods, getting the operating temp to the cooler end of it's range.