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Did you ever try for the Ontario Vehicles Info kit by Vin for the '68 SS?
There may be some luck w/ them gaining the LT-1 Vin by ETS-851 Plate # in the photo too?
Also, I don't know how far back it reaches or if even true but someone told me recently, your complete Ontario Vehicle ownership history w/ Vins is in the system w/ your Driver's License # also printouts available for a fee.
Best of luck w/ your backtracking!
~ Pete
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