[tom406]

Re-reading the original post, and confining our discussion to Chevrolet examples, I think it is safe to make some assumptions. Kelsey appears to be using the Dec '69 no-size/size cutoff for all Polyglas tires, GT or non. The fact that the '70 LS6 prototype was wearing sized Polyglas F-70-14 in the Oct '69 issue of CARS shows that the sized tires were available before this. My faith in the Dec '69 date is for Polyglas GT tires, the F-60-15 size in particular. There is ample evidence that the 14" Polyglas versions had the sizes on them earlier than December. But as BKH alludes, were 14" Polyglas tires even available as OEM on the '69 Chevrolets? Noone has yet offered an example of an original '69 Camaro or Chevelle with F-70-14 Polyglas tires, just the Wide Treads. If you have an untouched low mileage car, particularly a late '69 production car, please take a minute to check the spare and report your findings!