I don’t understand how you can still get the guy’s name wrong
Creamie,
Easy, and if I recall correctly, this is not the first time I have made that mistake, and you have picked me up. It's all because I have an acquaintance called Deacon. I promise to try harder.
As to data, what data would you like. The problem of exhaust valve seats v. unleaded fuels or not an urban myth. As far as I an concerned, my own personal experience over quite a number of engines is enough for me.
If it really is a huge con. job, it is one of the most successful and enduring of all time. The 1986 lists of vehicles came from the vehicle manufacturer's themselves, on what basis they separated valve/valve seat suitability in various models for unleaded operation without modification I do not know, but I doubt they plucked it out of thin air --- not after their experiences with Ralph Nader.
If all they wanted to do was sell new cars, why did some offer conversion kits of one kind or another (ie: Jaguar selling valves and seats made of the same material as later generation -post mid 1980 - production)
In Australia, NSW DMT/RTA (or their predecessor?) NRMA, RACQ, RVAC etc were all suckered in, amazing!!
Tootle pip!!