Did some sleuthing and am probably only of minor help.
Used 2 books the Cdn GM parts book and Catalog of Canadian car ID numbers.
In 1955 the 7000 series wasn't used. The use of 7000 series only started in 1958. You say car is an L-8 and Cdn cars, if an 8 cylinder, were the new Chevy V-8 ( 265 cu in ). No where could I find a body style designated as 44.
In 1958 the 7000 series was used but I couldn't find a body style 46. You say engine style is L-6. Canadian cars would have been an overhead valve 261 cu. in. straight 6 cylinder or 265 or 348 V8
In 1959 a series 7519 is a Laurentian 6 cylinder ( 261 cu in ) 4 door sedan that had a list price of $3040 Canadain with a weight of 3790 ponds. Serial numbers started at 975190001 and went up.
Can you provide more info that we could use to dig deeper?