[slythorne]

If you are talking about overall by casting, not taking into any factors such as "painted/unpainted roof", short run variation such as "Cheetah base", and color such as the "Enamel White Camaro"... I would say the Superfine Turbine from 1973.

 

[slythorne]

That is a very good one, those castings are very tough to find and go for a lot of money. Then you'll get collectors who say that the Turbine isn't a true Redline, it didn't come out in that '68-'72 time period and it came out when all the castings were done in enamel and so on.
To me it is a Redline and like I said, a tough one to come across no matter the condition.

Redlines are redlines. I wouldn't call those collector true collectors

I can see some trying to break the redline era down as "Spectraflame Era", but there are exceptions to that rule. Do they also consider the Jack Rabbit special, Pit Crew Car, Snake, and Mongoose not real redlines? What about the enamel versions of the Mark IV and the Heavy Weight Semi cabs?