I pulled one of the panels off that covered the actual furnace. Inside is a big round tube, probably the porcelain enamel you're talking about. It is probably 1 1/2 ft wide and as tall as the furnace. The guy who tried to date it today thinks it's 1962, b/c of the 62 in the serial number (84AN-6203A). There's a catalog online (from 1962) that I linked a few posts back, and the interior of that furnace on the third page looks different than what i've got from that year. If you see that page, would you think mine is older based on the porcelain tube? Or does that not matter too much??? Thanks for all the help. Much appreciated. I also have a house with an American Standart/Sunbeam model (SGF-85), series E-8. He thinks that's 1956. Any thoughts?