Does anybody know when Chevrolet changed over to Astro Ventilation? Until recently i thought all '68 SS Chevelles had the one piece front windows but have seen several lately with vent windows.

You may have seen some 300 series cars.

All 68 Malibus and SS's had vent windows, Astro Ventilation started in 69.

I owned a '68 SS that i believe to have been built in late '68 and it didn't have vent windows the best i remember. Black car with red SS stripe and black vinyl bench seats. Hot, hot, hot and no air conditioner.

I'm not really sure if that was a possibility on a late production car, guess we need someone with a little more knowledge. I've personally never seen an original 68 without vent windows, there's always the possibility that it had it's doors swapped out with ones from a 69.