red58 - Obviously, you really know your stuff here and way more than me, however my core had a 57 mark on it, the heater itself really looks like it has been there the same amount of time as everything else and it is in two different factory manuals I have where the drawing is identical to mine. I was not aware there were 3 models though and only thought there was a standard (mine) and the deluxe.
Bob K
