The engine casting number does correspond to a Canadian 235. Interestingly, the 1112396 distributor codes to '54 passenger car with Powerglide for US service, and the date code is also mid '54. I don't have info on distributors used in the Canadian engines to know if they were different.
The original PN for the vacuum advance assembly is 1116076 for that distributor. NOS units pop up on eBay, sometimes for reasonable $. But, you should be able to get a replacement unit at several of the suppliers. By way of example, Chevs of the 40's has them:
Vacuum Advance Control Unit.
Doug
