I have magazines going back farther than '68, but I'd turned off on C&D and R&T very early due to their predominance of featuring European cars and bashing American cars..
Does anyone have copies of the magazines or ads William mentioned? I'm not doubting it but I need to 'correct' my memory if there were earlier cars than 1970 models with the Polyglas GT tires. I spent most of the '69 model year 'pricing' Chevelle SS396's at every dealer I came across. I finally got them down to a price that could be afforded by a lowly USAF A1C in late June of '69, but when I went to order what I wanted (around 4July), I was told that 30 June was the LAST date they could order a '69 model. I was told I could order a '70 model, but at that time, the dealers had no information on the looks of the car or the pricing...
so I waited, and when the '70's were introduced, I didn't like the 'bulked up heavy look' of the 70 Chevelles, and a friend of mine suggested I check into Roadrunners - his main point was the availability of the F60-15 tires on 15" rallye wheels (which I'd never heard of at the time); I told him I couldn't afford the extra $700 or so for the Hemi, but he told me I didn't have to.. I just had to order Hemi Suspension ($15 option); I also ordered the 15" rallye because they looked so good ($43 option). The tires/wheels made my Roadrunner totally unique at that time because no other cars were running them at that time (or so I've thought)..??