My 1991 Lexus LS400 requires premium.... it has a V8. I do not think the smaller Lexus that year (ES250) required premium, since it had the Camry engine).
As you can see on the photo of this LS400 instrument panel- it says "premium unleaded fuel only" above the fuel gauge..
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....and now that you mentioned it, under the hood either my 72' Caprice and/or 73' Grand Ville, it says either 91 or 93 octane recommended, but I always run 87 in them. I guess its where they have the HP V8s in them. I will have to look into this. I had totally forgot about that!
Whats strange is that at least on the 72' it says it will run on "low lead" or "no lead" gas.
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That's certainly odd. Not one of those cars you listed should require premium fuel. 