Try Affordable Appliance (I think they are in PA, too) - They found a compatible, original oven thermostat for my 56 GE range - it was a Hotpoint part,too!
Here is a thermo replacement chart from 1979. It looks like you need 2 different thermo's depending on which oven. GE reduced the number of replacements to 3 kits. Maybe this info will help you to track down one.
SteveD
Customline sez thanks and watch out for Ebay...............
Thanks to steved who put me in the right direction for the Hotpoint thermostat. I finally ended up going with AP Wagner and they are sending me a GE thermo kit in a few days. I found original GE part # WB21X5109 on Fleabay but this guy didn't think to look in the box and know that parts were missing from the kit. When I told him I was sending it back he said he didn't know that there would be adapters and screws with the kit. I wish everybody who sells on Ebay knew what they were doing. All I need to do now is find a thermo for the bottom part of the oven which has a longer capillary tube (about 52 inches). Does anybody know if an extension can be put on a smaller cap tube?
I'm glad to hear it's on the mend. I especially love the logo beneath the handle; O'Keefe and Merrit had something similar as well. Given that a capillary tube is filled with liquid and then sealed I wouldn't think it possible to extend one successfully but hopefully someone more knowledgeable than I am will have a solution.