no idea what the ohmage is, but can't imagine why there would be a difference for 56, same gauge, same engine ... the 55 2nd was a mechanical gauge, in 56 the electric gauge started, and didn't change, I've had a couple dozen 55-59 gauge sets here and they're 100% interchangeable and the numbers I gave have worked in various different years I've had, 6 or V8
your gauge does not read degrees, it reads "cold" - "hot", and that's how any sender works, as the engine temp goes up, the resistance changes, doesn't matter the exact value, if you want to know what the gauge is telling you in degrees, you need to use a good digital thermometer on the engine/rad and compare, always a good idea because original gauges are not precision instruments
also with that 350, make sure you don't run the recommended 14# cap on the original rad, 350's will develop that much pressure, your rad and particularly rad core, won't be happy
edit: realized why 56 might be different, the threaded hole in the head of the 235 was still the smaller size hole for the mechanical sender - meaningless for your modern engine
Bill
