Keep plugging away...something will turn up. .
A couple more thoughts, if an engine is bad a testing and there's no extra correct suffix engines at hand could this number be a plant replacement unit? . Weren't CE's only a parts or service replacement at the dealer level? .
And did you get a copy of the microfilm Vin-Shipping list w/ other cars shown? . If so are there any other L36 big cars on the page and what engine suffixes are they? .
~ Pete