Got GenIV ac I know plenty are sold,so someone knows,I want add astro vents I need a template to avoid killing the dash.I ordered the repop astro vents which look better than va units.I did't know that these actually hook under dash.I know the size of hole,but location to start I don't.And what kinda hole saw did you use.

Don't the holes actually have a tab/lip on the stock vents? I am not by my 68 at the moment but recalled the astro vent openings being more than just a hole.

I dunno but if it were me, Frank from Prodigy customs would be the person I ask. Frank knows his stuff and I trust his advice, ihe does this stuf for a living.

Yes,they look to be more than just a hold,kinda egg shaped.